ratkil:
Due to the way liability suits are proliferating these days, many shops will only replace parts for critical systems like brakes. If rotors are warped, they no longer turn them on a lathe - if they do, and the car is subsequently involved in an accident(for whatever reason), they can expect to be party to a lawsuit.
Always ask for the old parts, and if you have doubts - ask them to show you exactly why replacement was needed. If you still have doubts, then take the parts to another shop for a 2nd opinion.