That depends on your industry requirements?
We are a Pharm/GLP lab. We do a:
[list]
[*] Calibration across the usable range.
[*] Ten reps of the weight used for daily drift check to determine mean weight.
[*] Daily range verification (three weights used in daily performance verification, (data from full calibration)
[*] USP uncertainty (ten reps of minimum weight, 3*RSD