The discs brand new are app. .125
When they get down to .108-.110, we toss them.
In addition to discs, we check the floater for warp, and usually end up replacing the floater.
We rebuild clutches for $50 labor plus parts. Our typical rebuild consists of discs, floater, and freshly ground plates. We also clean and inspect all your hardware and levers, as well as checking the spring rate to make sure all are matched correctly