Where would the checking cycle end? If I buy a set of gage blocks from the manufacturer and it includes a certificate of calibration and traceability to NIST, why would I immediately send it out for calibration? If shipping from the manufacturer invalidates the certificate due to "unknown shipping and handling conditions", wouldn't the same apply when shipping back to me from the calibration house? I think it would suffice to perform visual examination of the blocks to check for obvious physical damage.