Rules of Thumb for Calibration:
How often should we calibrate?
For standard histology:
-20 uL & smaller: every 12 months
-200 uL to 1000uL: every 18 months
Decrease this interval if the pipette has been dropped/abused in any way. Calibrate immediately if you can see the drift in the volume, or if two of the same size pipette draw visibly different volumes from each other.
If they are getting heavy use, we should decrease the interval to about 6 months, otherwise the above intervals are fine.
Things to consider:
Smaller pipettes (2, 10, 20 uL) show volume changes faster
p20 (1) *for virus injections only