There was a time when choosing a gaging solution for shaft-type parts was a relatively straightforward task. High-volume parts received a custom-built gage and everything else received a manual or automatic “snap-on” or ring gage of some sort. The gages used either air or contact technology and anything beyond those basic capabilities tended to reside in a metrology lab.
Things are a good bit more complicated today because you have a lot more choices in terms of hardware, software and gaging technology. Now you have to weigh factors including: