Somewhat against the thread ..
I have a big collection of Very Good import chinesium calipers and digitals mics, both for my own use and for limited resale.
I bought 5 different brands to test, as 1" digital mics, and found a really good brand I was happy with.
Change the batteries about 1 / year on about 8 of, that I use myself.
Digital 1 micron mics to 6", plus 2 sets of 100 and 150 and 200 mm digital calipers.
The digital mics are accurate to as good as japanese mitutoyos, about 1-2 microns, based on multiple blind tests with gage pins.
The calipers are about as good as the best Mitutoyos, or similar US federal or Mahr stuff.
About +/- 0.01 mm throughout the range.
I buy the 2032 batteries in sets of 20 and they last me a few years.
The digital mics are much faster and more accurate than the traditional mechanical ones, have 2 sets of.
Generally, the digital mics are about +/-1 unit or 1 micron off, at most, and almost always trending only in one direction.
Upwards, iirc.