Is there a more sophisticated tool than Rohloff HG-Check
I bought one too - on the same idea of having a better way to check for chain/cassette wear.   Its pretty useless to be honest.

The best tool for knowing how much mileage is on a chain/cassette is a set of accurate records.   Cars have mileometers/odometers and stationary engines have hour meters.  Sadly bikes don't have the same hardware.

So I record every ride on Strava, and religiously use the "My Gear"* options to note when things were changed.  Works for me

* For clarity, that's "gear" in the sense of "equipment", rather than specifically gears as in cogs.



But records don't help where you have a bike with unknown provenance.  For those you have to fire up the eye-crometer and make an educated guess.   And ride it, if feasible.  You can find more faults quicker in a 30 second ride than any other way.