(OK, some licence has been taken with the wording of the question!)

Instrument calibration is often thought to be expensive but the information contained in the resultant certificate is usually worth considerably more. This is not always appreciated and, on receipt, many certificates are wastefully consigned to drawers, shelves or even wall plaques. Purchasers should review their expectation of an instrument before requesting a calibration - to ensure that the calibration is likely to meet their needs. For example, with a pressure balance calibration certificate, proper consideration of gravity, temperature, calibration results, change of values between calibrations and the uncertainty of the calibration can improve the achieved accuracy ten-fold. Calibration certificates should not be consigned to a drawer, shelf or wall plaque but the information contained therein should be acted upon.