Rotor Specs
 

Where can I find the minimum rotor thickness for a vehicle? I have a friend that wants to be armed w/info before getting her car serviced. She's concerned they'll sell her rotors she doesn't actually need when her current ones can still be serviced.

The vehicle in question is a 2000 Audi A6-T AWD. I will try the service dept for Audi when they open but thought I would check other avenues as well.
Thanks.