When looking at your rotors the this to look for are:
- Thickness, minimum thickness for standard brake discs is 24.9mm
- When checking thickness be sure to use a brake rotor micrometer or caliper. They have a point that allows you to check thickness as well as depth of any scoring on the rotor.
3. Cracking or heat checking. This can happen if you are using your car on the track and are using any heavy braking. Small minor heat checking is normal but should be monitored. If you find any cracks that extend to the outer perimeter of your rotor, that rotor should be replaced.