first, welcome back (it’s been a long way for cookie and it sounds like for you as well)…
there is a way to deal with measurement in Blender…
to start the default cube in the default scene is 2 Blender units x 2 B.U. x 2 B. U.
this is assumed as 1 B.U. = 1 M

1. is under the scene tab in properties panel find…
2. the units…
3. the increments and
4. whether blender units, imperial or metric
Blender is precise enough with it’s measurements to be able to run a CNC machine, or so it is said…
hope this helps…
😀