Well recently on my YouTube channel I was told that digital calipers were not okay and are inaccurate for measuring minimum rotor thickness (the calipers without points). Just to clarify for my viewers and subscribers it is ok, in most cases, to use these type of calipers on a min thick check, and they are more accurate than a combination wrench lol. The times it would not be acceptable to use that type of calipers, shown in the commented video, is when there is an outer ridge on the rotor, or if there are any deep grooves in the rotor. Also, apparently if you are an inspector in a state where they require you to use a micrometer to check rotors during an inspection, then calipers would also not be acceptable haha. Anyways, for the general public, you're fine just using a regular set of calipers to make this measurement, unless under one of the conditions. Now if you were a mechanic you would use a micrometer to see what the deepest groove was to see if you had enough room left, which would determine if you were able to resurface it or not. And there's even more measuring tools out there for other task like determining whether the rotor is within lateral run out, and out of round specs. But my videos are not target towards technicians working in shops. So to sum it up, the debatable calipers in my video are okay in most cases, and are very accurate (measure down to .0001 inch, paper is .0003 inch); although, a set of calipers with points, or a micrometer with pointy ends would be better.