What are the minimum tolerances for brake pads/shoes?

The front brake pads minimum thickness is 2mm and the rear brake shoes is 1.5mm. Any less and they must be replaced. Inspect regularly at 20k mile intervals.

Do not allow brakes to go unserviced or you will cause additional wear at additional cost to fix (such as scoring the rotors, typically happening at the stage where the front brakes squeal and screech when applied).