[RKDinOKC]

At 73K miles my car is NOT a collector's car.
My car is an enlthusiasts car. Not super low miles. but not high miles for a 94.
It also is not completely original. But has been upgraded with the proven upgrades that enthusiasts make that while adding performance to not take away reliability. And are done as the original items wear.

So in many ways, to me, and enthusiasts car in excellent condition is better than a collector's car. no matter how thick the paint is if it looks good.
Especial considering a collectors car with the original things like seals etc are made from rubber good that will dry out and fall apart or leak when not used.

I waxed a LOT of cars when I was younger and completely understand takiing off too much paint on older single stage paint. There is a point when the vehicle needs re-painted. However with more modern two stage or clear coated paints a new fresh clear coat can really vitalize paint much cheaper and without much hassle.

The only place I've seen depth gauges used is to determine whether paint needs fresh clear coat before protecting with waxes/sealants or if they can go ahead an polish the clear coat without harming the color coat.