Do not machine these composite rotors on a short interval. Replace the front brake pads about every 25,000 to 30,000 miles so the rotors are not damaged. If machining has gone through the roughly 0.015-inch hard surface into softer material, replace the rotors instead of turning them further.
The owner of a 2005 Lexus RX330 with about 23,000 miles was told by a dealer that turning the brake rotors was normal and should be expected every 20,000 to 23,000 miles. The expert said that is not correct. These rotors are composite with only about 0.015 inch of hard material, so turning below that exposes softer material. Replacing the front pads every 25,000 to 30,000 miles should prevent rotor damage, and rotors can last well over 100,000 miles without being turned.
