Time, expense, and location How much time and money you want to spend on calibration will dictate where you decide to have your gages calibrated. Before deciding where to calibrate, you must determine how much downtime you can afford for each gage. If you use your gages on a daily basis, you may have a backup supply of calibrated gages to use while the original ones are being recalibrated. There is always one working instrument on hand so that downtime isn't a problem. If your backup gages are just for emergencies and not accurately calibrated, downtime becomes a crucial factor.
Some labs perform calibrations within a few days, others within one or two weeks.
NIST can take up to 40 days to calibrate a set of gage blocks. An in-house calibration lab usually has the fastest turnaround time and is a logical solution if you use thousands of gages. However, the initial investment you'll have to make in calibration equipment must be considered. I initially calculated that the company's investment in calibration equipment would pay for itself in three years, but now it's down to 15 months. No matter how much you are willing to spend on calibration, the level of accuracy you need may not allow you much of a choice.