# Pipette Maintenance Log: A Free Template to Track Cleaning and Care By the end of this guide you will be able to build a working pipette maintenance log from a free template, record every cleaning, decontamination, and calibration event with the fields that matter, set automatic due-date reminders in a spreadsheet, and run a simple gravimetric check that tells you whether a pipette still meets its accuracy specification before you log it as serviced. You need a spreadsheet application such as Excel, Google Sheets, or LibreOffice Calc, a list of your pipettes with model names and serial numbers, 70% ethanol and lint-free wipes for routine cleaning, and, for the calibration check described later, access to an analytical balance and a bottle of distilled water. The pipette maintenance log template below takes about ten minutes to set up and scales from a two-person teaching lab to a forty-pipette core facility. ## Why a Pipette Maintenance Log Matters An air displacement pipette is the workhorse of a [molecular biology](/blog/careers/molecular-biology) bench. A spring-loaded piston pulls a column of air above the liquid, and a seal around the piston keeps that air column airtight. Every part of that system wears with use. Piston seals dry and crack, grease migrates or washes away, solvent vapor corrodes the spring and shaft, and a single drop onto the floor can bend the shaft enough to shift every delivered volume. Accuracy drift is gradual and invisible. A pipette that passed calibration in January can be out of specification by summer with no change in how it looks or feels. Manufacturer service documentation exists precisely because these failure modes are predictable, and their care procedures pair cleaning with periodic verification. A log turns that predictability into a schedule. The log also protects your data. DNA and RNase survive on plastic surfaces and transfer through aerosols generated during aspiration. If your log shows that every pipette in the RNA room was decontaminated on the fourth of the month, you can rule the pipettes in or out when a contamination pattern appears. Without dates, you are guessing. Quality systems built on Good Laboratory Practice expect dated, documented maintenance for measurement equipment, and the maintenance log is the record a quality officer or auditor asks to see first. The same record answers the everyday question that follows an assay failure. If triplicate quantitative PCR reactions start disagreeing, check the log before you blame the master mix. A P200 that was dropped three weeks ago and never rechecked is a better first suspect than a reagent lot. A pipette maintenance log and a pipette calibration program are two halves of one system. The log schedules the work, records who did it, and stores the result. Calibration is the measurement that fills the result column. Laboratories that track both catch drift early, repair pipettes before they fail outright, and spend less on replacement. ## What Goes Into a Pipette Maintenance Log A useful log has one row per event and a fixed set of columns. Each field earns its place by answering a question you will actually ask later. 1. **Pipette ID.** A unique label physically attached to the instrument, such as colored tape with a code. A practical convention combines location and nominal volume, for example PIP-B2-1000 for the 1000 µL pipette on bench 2. Do not rely on the serial number alone at the bench, because nobody reads serial numbers mid-experiment. 2. **Model and serial number.** The model tells you the volume range and whether the instrument is autoclavable. The serial number is what an external calibration provider matches against its certificate. 3. **Volume range.** For example 100 to 1000 µL. Accuracy limits differ across the range, so the range belongs in the record. 4. **Location and primary user.** A pipette that lives in the RNA room has different decontamination needs than one shared on the cloning bench. 5. **Date.** Write dates as YYYY-MM-DD. ISO format sorts correctly in every spreadsheet and removes ambiguity about whether 03/04/2026 means March 4 or April 3. 6. **Action.** Use a fixed vocabulary (see the table below) so filters and pivot tables work. 7. **Performed by.** Initials are enough if the lab keeps a key, but full names survive staff turnover better. 8. **Result.** Pass or fail for verification events, or a short observation such as "no residue found" for cleaning events. 9. **Next due.** The date the next calibration or check is due. This is the column your spreadsheet formulas will use. 10. **Notes.** The numbers. Systematic and random error from a calibration check, the reason for a repair, the circumstances of a drop. Future you reads these, so present you should write them. Some labs split the file into two tabs, a master inventory with one row per pipette holding the static fields, and an event log holding the dated rows. The single-file layout below works well up to a few hundred events per year. | Log action | What you actually do | Typical interval | |--|--|--| | Daily wipe-down | Wipe the exterior with 70% ethanol and check the nose cone for residue | Every use session | | Leak test | Aspirate water, hold the tip submerged, and watch for bubbles | Monthly, and after any drop | | Deep clean | Disassemble the nose cone, clean the piston and seal, regrease per the manual | Every 3 to 6 months, or when the plunger feels stiff | | Decontamination | Treat the lower assembly for DNA, RNase, or chemical residue | After known exposure, or before moving between labs | | Autoclave | Steam sterilize at 121 °C for about 20 minutes if the model is rated for it | As needed, then recalibrate | | Calibration check | Ten gravimetric weighings at one volume to confirm the pipette holds its limits | Every 6 to 12 months, and after drops, repairs, or autoclaving | | Full calibration | Gravimetric test at three volumes with a certificate | Annually, or on the interval your quality system sets | These intervals are common laboratory practice, not universal rules. A pipette that dispenses volatile solvents all day needs service sooner than one that pipettes buffer twice a week. Your standard operating procedure sets the final numbers. ## The Free Pipette Maintenance Log Template ### Pipette Maintenance Log Template Format The template comes in two formats. The CSV version pastes straight into any spreadsheet. The printed table version lives in a bench binder for labs that prefer paper at the point of use. Both use the same columns, so you can run paper at the bench and transcribe to the spreadsheet weekly. ```csv Pipette_ID,Model,Serial_Number,Volume_Range_uL,Location,Date,Action,Performed_By,Result,Next_Due,Notes PIP-B2-1000,Research plus 1000,AB12345,100-1000,Bench 2,2026-05-11,Calibration check,J. Rivera,Pass,2026-11-11,"Sys +0.09% at 1000 uL" PIP-B2-200,Research plus 200,CD67890,20-200,Bench 2,2026-05-11,Deep clean,J. Rivera,Pass,,"Piston regreased, plunger smoother" PIP-RNA-10,Research plus 10,EF24680,1-10,RNA room,2026-05-12,Decontamination,M. Chen,Done,,"RNase decon solution applied and rinsed" ``` Three formatting rules keep the file healthy. First, keep the header in row 1 and data starting at row 2, because every formula in the walkthrough below assumes that layout. Second, keep commas out of individual fields, or wrap the field in double quotes as the Notes column does above. Third, keep one row per event, even when two pipettes were serviced the same day. For a printed bench copy, use the same columns on paper: | Pipette ID | Model | Date | Action | Performed by | Result | Next due | Notes | |--|--|--|--|--|--|--|--| | | | | | | | | | | | | | | | | | | | | | | | | | | | ### A Filled-In Pipette Maintenance Log Template Example The fastest way to understand the format is to read a service history. Here is one year for PIP-B2-1000, the 1000 µL pipette on bench 2. | Date | Action | Performed by | Result | Next due | Notes | |--|--|--|--|--|--| | 2025-11-10 | Full calibration | External service | Pass | 2026-11-10 | Certificate filed, sys +0.4% at 1000 µL | | 2026-02-03 | Deep clean | J. Rivera | Pass | | Piston regreased, plunger smoother | | 2026-04-22 | Drop incident | M. Chen | Tip ejected on impact | 2026-04-23 | Fell from bench height onto floor | | 2026-04-23 | Calibration check | J. Rivera | Pass | 2026-10-23 | Sys +0.09% at 1000 µL | | 2026-08-30 | Leak test | M. Chen | Pass | | No bubbles after 30 s submerged | Read the story the log tells. The pipette was calibrated in November. A deep clean in February was routine. The drop in April triggered an off-cycle calibration check the next day, which passed, so the pipette stayed in service with a new due date. When a reviewer later questions data generated between April and October, the log shows the instrument was verified after its last known shock. That is the difference between a maintenance log and a pile of sticky notes. ## Building the Log in a Spreadsheet, Step by Step The walkthrough uses Google Sheets, and every formula also works in Excel unless noted. Start from a blank sheet and paste the CSV header row into cell A1. **Step 1. Paste the template and freeze the header.** Paste the CSV block from the previous section into cell A1. Then open View > Freeze > 1 row so the headers stay visible while you scroll. Your sheet now has columns A through K, with row 1 holding Pipette_ID through Notes. **Step 2. Format the date columns.** Select columns F (Date) and J (Next_Due), then open Format > Number > Date. Dates entered as 2026-05-11 will right-align, which is the visual confirmation that the sheet parsed them as dates and not text. Left-aligned dates are text, and text breaks every formula below. **Step 3. Add the action dropdown.** Select column G, open Data > [Data validation](/blog/data-analysis/data-validation-excel-dropdown-rules), and add a dropdown with this list: ```text Daily wipe,Leak test,Deep clean,Decontamination,Autoclave,Seal and grease service,Calibration check,Full calibration,Repair,Drop incident ``` In Excel the same control lives under Data > Data Validation > Allow: List. A fixed vocabulary is what makes filters work later. **Step 4. Calculate the next due date.** In J2, enter: ```text =IF(OR(G2="Calibration check",G2="Full calibration"),EDATE(F2,6),"") ``` EDATE(F2,6) returns the date six months after the event. The IF wrapper fills Next_Due only for calibration rows, leaving cleaning rows blank. With F2 = 2026-05-11, the expected output in J2 is 2026-11-11. Copy the formula down column J. If J2 shows a plain number instead of a date, format the cell as a date. **Step 5. Flag overdue pipettes.** In N2, enter: ```text =IF(AND(J2<>"",TODAY()>J2),"OVERDUE","OK") ``` With J2 = 2026-11-11 and today's date before that, the expected output in N2 is OK. After the due date passes, the same cell reads OVERDUE. Copy down column N, and put the header Status in N1. **Step 6. Estimate cycles since service.** Wear follows usage as well as the calendar. Put the header Avg_Daily_Cycles in L1 and enter the average number of deliveries per day for that pipette, for example 150 for a busy quantitation bench. Put the header Est_Cycles_Since_Service in M1 and enter: ```text =(TODAY()-F2)*L2 ``` With F2 = 2026-05-11, L2 = 150, and today = 2026-11-11, the elapsed time is 184 days, so the expected output in M2 is 27600 cycles. When that number climbs past the service threshold your SOP sets, schedule service even if the calendar date has not arrived. **Step 7. Highlight overdue rows.** Select A2:K1000, open Format > Conditional formatting, choose Custom formula is, and enter: ```text =AND($J2<>"",$J2 Conditional Formatting > New Rule > Use a formula. **Step 8. Build the overdue list.** In a second tab named Overdue, put this formula in A1 for Google Sheets: ```text =IFERROR(FILTER(Log!A2:K1000,Log!N2:N1000="OVERDUE"),"Nothing overdue") ``` In Excel 365, FILTER accepts a third argument directly: ```text =FILTER(Log!A2:K1000,Log!N2:N1000="OVERDUE","Nothing overdue") ``` Expected output: the rows for any pipette whose Status reads OVERDUE, or the single line Nothing overdue. This tab is what you project at a weekly lab meeting. | Goal | Formula | Example result | |--|--|--| | Next due date, 6 months out | =IF(OR(G2="Calibration check",G2="Full calibration"),EDATE(F2,6),"") | 2026-11-11 | | Overdue flag | =IF(AND(J2<>"",TODAY()>J2),"OVERDUE","OK") | OVERDUE | | Estimated cycles since service | =(TODAY()-F2)*L2 | 27600 | | Overdue list | =IFERROR(FILTER(Log!A2:K1000,Log!N2:N1000="OVERDUE"),"Nothing overdue") | Filtered rows | **Spreadsheet errors you will actually see, and the fixes.** - **#NAME?** EDATE shows this when the function name is misspelled or, in older Excel versions, when the Analysis ToolPak add-in is disabled. Check the spelling first, then enable the add-in under File > Options > Add-ins. - **#VALUE!** One of the date cells contains text, usually a date typed with a stray character or a locale mismatch. Re-enter the date as 2026-05-11 and confirm the column is date-formatted. - **#REF!** A column or row that a formula referenced was deleted. Undo the deletion, or rebuild the formula with whole-column references such as F:F. - **#SPILL!** In Excel, the FILTER output cannot expand because cells below the formula are occupied. Clear the cells under the formula. - **No matches are found in FILTER evaluation.** In Google Sheets, this means no row currently reads OVERDUE, which is good news. The IFERROR wrapper replaces it with Nothing overdue. Verify the build with one test row. Enter a pipette with a date one year in the past and confirm that J2 lands six months later, N2 reads OVERDUE, and the row turns red. Then delete the test row. Once the sheet runs, restrict edit access to the two or three people who maintain the log, rely on version history to answer who-changed-what, and archive a copy at the end of each year. Review the Overdue tab in a weekly lab huddle, assign each overdue pipette an owner and a date, and the log becomes self-sustaining. ## Daily Pipetting Technique That Extends Service Intervals Technique is maintenance you perform with every delivery. Careless pipetting is a major source of both inaccurate volumes and premature repairs, and the habits below follow the technique guidance published by major pipette manufacturers. - **Seat the tip fully.** Press and twist until you feel it seat. A loose tip leaks air, and a leak looks exactly like a calibration failure. - **Hold the pipette vertical when aspirating.** A tilted pipette changes the hydrostatic pressure at the tip opening, and the volume error grows as the volume shrinks. - **Immerse the tip to the right depth.** Too shallow and you aspirate air, too deep and liquid films the outside of the tip and eventually the nose cone. | Volume per delivery | Typical tip immersion depth | |--|--| | Up to 10 µL | 1 to 2 mm | | 10 to 100 µL | 2 to 3 mm | | 100 to 1000 µL | 3 to 6 mm | | Above 1 mL | 5 to 8 mm | These depths are typical published guidance for air displacement pipettes. The principle is simple, deep enough to keep the tip opening submerged through the whole aspiration stroke, shallow enough to keep the shaft clean. - **Keep a consistent rhythm.** About one second of aspiration, a one-second pause with the tip still in the liquid, then dispense. Rushed aspiration leaves residual liquid in the tip and inconsistent volumes in the plate. - **Pre-rinse the tip.** Aspirate and dispense the working liquid two or three times before the measured delivery. Pre-rinsing equilibrates the air inside the tip with the vapor pressure of the liquid, which improves accuracy with volatile solvents, viscous samples, and small volumes. - **Dispense against the wall.** Touch off along the receiving vessel wall to recover the film of liquid that clings to the tip. - **Match the mode to the liquid.** Forward pipetting, first stop to aspirate and first stop plus blow-out to dispense, suits aqueous buffers. Reverse pipetting, second stop to aspirate and first stop to dispense with the excess left in the tip, suits viscous, foaming, or volatile liquids. - **Equilibrate temperatures.** Let cold reagents, the pipette, and the tips reach room temperature before measuring, because temperature differences between the liquid and the trapped air column shift delivered volumes. - **Never lay a loaded pipette flat.** Liquid runs into the nose cone and corrodes the seal and spring. Stand it upright in a rack or return it to the stand. - **Store unloaded and upright.** Hang the pipette on a stand, and set the volume to the top of the range so the spring rests relaxed, which many manufacturers recommend. - **Use barrier tips for dirty work.** Aerosol-resistant (filter) tips stop aerosols from reaching the piston during aspiration. They protect the pipette internals and prevent carryover, and they complement maintenance rather than replacing it. ## Cleaning, Decontamination, and Autoclaving ### External Cleaning After each session, wipe the exterior with 70% ethanol on a lint-free wipe, including the tip ejector, which collects drips. For sticky residues, use a mild detergent solution, then ethanol, then dry. Keep liquids away from the volume display window and the ejector mechanism. ### When Liquid Enters the Nose Cone ![Six steps from removing the tip and taking apart the nose cone through rinsing, checking seals, regreasing, and a calibration check.](/article-images/illustrations/pipette-maintenance-log-template-nose-cone-response.webp) This is the most common repairable failure, and speed matters. Vapor from even a microliter of salt solution or organic solvent corrodes the piston spring and degrades the seal within days. The nose cone is the detachable lower assembly that houses the shaft and piston seal. The response: 1. Remove the tip and eject it. 2. Disassemble the nose cone per your model's manual. Most models release it with a tool or a quarter-turn. 3. Rinse the affected parts with distilled water, then ethanol, and dry completely with a lint-free wipe. 4. Inspect the seal and O-ring for swelling, cracks, or flat spots. Replace them if damaged. Seal sets are inexpensive and model-specific. 5. Apply a thin film of the silicone grease specified in the manual if your model calls for it. The wrong grease can swell seals. 6. Reassemble, then run a calibration check before the pipette returns to service. ### Decontamination for DNA, RNase, and Chemicals Routine 70% ethanol wipes reduce general residue. For DNA decontamination, wipe the lower assembly with a fresh 1:10 dilution of household bleach, roughly 0.5% sodium hypochlorite, let it sit briefly, then rinse with water and dry, because chlorine corrodes metal over time. Commercial DNA-degrading reagents work without the corrosion risk. For RNase, use a commercial RNase decontamination solution on the exterior and nose cone, since RNases are robust enzymes and ethanol alone does not inactivate them reliably. Treat UV as a surface tool for tips and work surfaces rather than a pipette cleaning method, because prolonged UV exposure embrittles plastics and seals. ### Autoclaving Manufacturers such as Eppendorf and Gilson document steam autoclaving at 121 °C for about 20 minutes for their autoclavable models, with model-specific instructions on whether the instrument must be disassembled first. Check your manual before anything goes into the chamber. Autoclaving a pipette that is not rated for it warps the housing and destroys the seals. After any autoclave cycle, let the pipette cool and dry completely, regrease if the manual requires it, and run a calibration check, because sterilization can shift the delivered volumes. Treat post-autoclave verification as part of the cycle, not an optional extra. For concentrated acids, alkalis, and aggressive organic solvents, an air displacement pipette is the wrong tool. A positive displacement pipette, where the piston sits directly against the liquid inside a disposable capillary, keeps corrosive vapors out of the mechanism entirely. ## How to Verify Pipette Calibration Between Services The gravimetric check, meaning a check based on weighing, is the method behind every calibration certificate, and a simplified version runs on any lab balance in about twenty minutes. ISO 8655, the international standard for piston-operated volumetric apparatus including air displacement pipettes, defines the test, dispense replicate volumes of distilled water, weigh them, and convert mass to volume. ### The Gravimetric Check 1. Let a bottle of distilled water, the pipette, and the tips sit on the bench until everything reaches room temperature, typically 20 to 25 °C. 2. Confirm the balance reads to 0.1 mg and carries a current calibration sticker. For volumes below 100 µL, use a balance that reads to 0.01 mg, because 0.1 mg is 0.5% of a 20 mg sample and would swamp the measurement. 3. Set the pipette to the test volume. Nominal volume, the top of the range, is the standard first test. ISO 8655-based calibration also tests 50% and 10% of nominal, where relative errors are largest. 4. Tare a small vessel on the balance with the doors closed. For deliveries of 100 µL or more, an empty weigh boat works. For smaller volumes, pre-load the vessel with a small amount of water, tare, then dispense into it to limit evaporation. 5. Pre-rinse a fresh tip, aspirate from the water bottle with a steady rhythm, and dispense into the vessel. Record the mass, tare again, and repeat for 10 deliveries. 6. Convert each mass to volume with the Z factor, then compute the mean, the systematic error, and the random error. ### Converting Mass to Volume With the Z Factor ![Worked example converting a mean mass of 997.59 mg of water at 22 C into 1000.88 uL using the Z factor 1.0033.](/article-images/illustrations/pipette-maintenance-log-template-z-factor-volume.webp) The Z factor converts the mass of water to the volume it occupied at the test temperature, accounting for water density and air buoyancy. The formula is V = m × Z. Standard tabulated values: | Water temperature | Z factor (µL/mg) | |--|--| | 20 °C | 1.0029 | | 21 °C | 1.0031 | | 22 °C | 1.0033 | | 23 °C | 1.0035 | | 24 °C | 1.0037 | | 25 °C | 1.0039 | These are the standard gravimetric conversion factors used in pipette calibration work. ```text Pipette: 1000 uL model, set to 1000 uL Water temperature: 22 C, Z factor = 1.0033 uL/mg Ten replicate masses (mg): 997.4 998.1 997.0 997.9 997.6 998.3 997.2 997.8 997.5 997.1 Mean mass = 997.59 mg Mean volume = 997.59 x 1.0033 = 1000.88 uL System error = 1000.88 - 1000 = +0.88 uL (+0.088% of target) Std deviation = 0.43 mg -> 0.43 x 1.0033 = 0.43 uL Random error = 0.43 / 1000.88 = 0.043% CV Typical limits at 1000 uL: systematic +/-8 uL, random <=3 uL Verdict: PASS ``` The systematic error (accuracy) is how far the mean delivery sits from the set volume. The random error (precision) is the scatter around that mean, reported as the coefficient of variation, the standard deviation divided by the mean. ### Judging the Result Against Error Limits Compare your errors to the limits the manufacturer publishes for your model. Typical limits at nominal volume for common air displacement models are: | Pipette | Test volume | Typical systematic error limit | Typical random error limit | |--|--|--|--| | P20 (2 to 20 µL) | 20 µL | ±0.2 µL (±1%) | ≤0.1 µL (0.5%) | | P200 (20 to 200 µL) | 200 µL | ±1.6 µL (±0.8%) | ≤0.6 µL (0.3%) | | P1000 (100 to 1000 µL) | 1000 µL | ±8 µL (±0.8%) | ≤3 µL (0.3%) | These limits come from ISO 8655 and manufacturer specification sheets, so confirm the sheet for your exact model before you judge a result. The two errors fail differently. A worn seal usually shows up as rising random error first, while a misadjusted volume setting shows up as systematic error. ### How to Check Your Work Run the full 10-weighing sequence a second time. The two means should agree within a fraction of the random error limit. Verify the balance with its internal calibration or a check weight before you start. Watch for bubbles clinging to the vessel wall, which inflate the mass. Cross-check with a second pipette of the same nominal volume, and if both read high by the same amount, suspect the water temperature you entered rather than the pipettes. If the pipette fails, clean and regrease the piston assembly, then retest before you declare it out of specification. ### When to Send the Pipette Out for Service Send a pipette to an accredited calibration provider for a full calibration when it fails a gravimetric check after cleaning, after any mechanical repair, on the annual cycle your quality system sets, and whenever the log shows a pattern of drift. Manufacturer service guidance recommends setting the interval from usage and verifying after events such as autoclaving or repair. A full service typically includes disassembly, seal and O-ring replacement, regreasing, calibration at three volumes, and a certificate listing the as-found and as-left errors. Record both in your log, because the as-found values tell you how fast that pipette drifts. ## Common Mistakes and Limitations 1. **Testing only the nominal volume.** Relative errors grow as volume shrinks, and a pipette that passes at 1000 µL can fail badly at 100 µL. Add a 10%-of-nominal test. 2. **Treating a calibration check as a full calibration.** Ten weighings at one volume confirm performance, they do not adjust it. Only a full calibration with adjustment resets the instrument. 3. **Skipping the post-autoclave check.** Sterilization moves seals and grease. Verify before the pipette dispenses anything that matters. 4. **Writing "cleaned" with no initials, no date, and no observation.** An entry you cannot trace is an entry an auditor will strike. 5. **Sharing pipettes without logging the handoff.** When contamination appears, the first question is who used the pipette between the clean sample and the dirty one. 6. **Blaming calibration for what tips cause.** A poor tip fit leaks air and mimics calibration failure. Always test with the tip brand you actually use. 7. **Storing pipettes loaded or horizontal.** Both drive liquid into the mechanism. Store upright on a stand, unloaded. 8. **Ignoring the cycle count.** A pipette on a high-throughput bench ages in months what a teaching lab pipette ages in years. Same calendar, different wear. 9. **Backfilling entries before an audit.** Falsified maintenance records undermine every record in the lab, including the data. The intervals and limits in this article reflect typical laboratory practice and published manufacturer specifications, and they do not replace your institution's standard operating procedure or the certificate from an accredited calibration provider. Individual pipettes and individual labs need their own documented program. ## Frequently Asked Questions ### How often should a pipette be calibrated? Most laboratories verify pipette calibration every 6 to 12 months, and immediately after a drop, a repair, an autoclave cycle, or any assay result that suggests drift. High-use pipettes need shorter intervals. ### What is the difference between cleaning, decontaminating, and calibrating a pipette? Cleaning removes visible residue, decontamination inactivates DNA, RNase, and chemical carryover, and calibration measures and corrects the volumes the pipette actually delivers. A pipette can be spotless and still out of specification. ### Can I autoclave my pipette? Only if the manufacturer lists your model as autoclavable, and then at 121 °C for about 20 minutes with any disassembly the manual requires. Run a calibration check after the pipette cools and dries. ### What should I do if liquid gets inside the pipette? Stop using it, disassemble the nose cone, clean and dry the piston and seal, replace damaged seals, regrease if the manual calls for it, and run a calibration check before the pipette returns to service. ### How can I tell a pipette needs calibration without a balance? Warning signs include a stiff or gritty plunger, bubbles or leaks at the tip, visible residue in the nose cone, and replicate volumes that visibly disagree. Only a gravimetric check confirms the error, so treat the signs as a reason to schedule one. ### What information must a pipette maintenance log include? At minimum, a unique pipette ID, the date, the action performed, who performed it, the result, and the next due date. Model and serial number, location, and notes round out the template above. ### Is a paper log or a spreadsheet better? A spreadsheet sorts, filters, and calculates due dates automatically, while a printed sheet survives at the bench where a keyboard does not. Many labs run paper at the point of use and transcribe to the spreadsheet weekly. ### Do filter tips make pipette maintenance unnecessary? No. Filter tips block aerosols from reaching the piston, but they do nothing about seal wear, solvent vapor corrosion, or mechanical damage. They complement maintenance rather than replacing it.