I keep my own little "bureau of standards" in the shop. Things like standards for setting and checking mikes and calipers,granite surface plates,squares and straight edge(all black granite) are good to have. Actually,pink granite makes a better wearing surface plate. But,in a home shop environment,you aren't going to wear out any granite!

What you say is true about temperature,but for wood working tolerances,I wouldn't worry much. Don't forget about NOT handling precision mikes,levels,etc. with bare(hot) hands. When I level my lathes,I wear gloves to not warp the Starrett #199 level,which is very accurate and sensitive to heat.

If you are using dial calipers,lay them on the FACE to keep dust and chips out of the tiny little rack teeth. The most trouble I've had with dial calipers is they can sometimes jump the rack a bit,causing the needle to not zero in the vertical position. You can rotate the dial till it does zero,but that bugs me. They usually come with a thin little brass tool that you can insert behind the dial and correct the problem. READ the instructions. The gear that runs in the rack is very small and delicate.