What do you guys think of this vibration hour meter for keeping track of run time. Stick it near your spindle and no wires.
I don’t have any opinion of that device, but just wanted to say that Mach4 keeps track of spindle runtime, and I don’t know about Centroid, but I would guess it does to.
Mabye @Eric knows.
It does keep track of runtime. Only in the software though so if you upgrade it will get reset.
Oh! I ordered a few for a lawnmower an compressor and thought I’ll try one on the cnc too 
Good point, a device like this would be impartial to software reloads/updates/etc.
They make ones for air compressors that come with some (probably pretty bad) software that can remind you of scheduled maintenance. Amazon.com: Dewalt DXCM024-0393 Cordless Air Compressor Monitoring System with (3) AA Batteries : Tools & Home Improvement