[JimD]

I recently replaced my brake pads, not the rotors, on my e88 (admittedly a quite different BMW) at a little over 80,000 miles. The brake light had been on for some time but I checked the pads and they still had a lot of wear left. The sensor is quite thick so it gets touched and lights up the light when you still have around 1/4 inch of pad left. That is probably over 10,000 miles of material at my usage rated but I got tired of looking at the light in around 5,000 miles.

I got my drivers license in 1971 and have always maintained my own cars. I believe both machining and replacing rotors is usually unnecessary. I treat my BMW the same as my Japanese, American, and Korean manufactured cars. As long as the rotors are still thick enough and not damaged, I just put on new pads and go. The reason that repair places do not do this, however, is a little bit safety and mostly complaints. The safety angle is the fact that the pads have to wear a little bit to have full contact with a used rotor. So your stopping distance is slightly longer for 100 miles or so. I very rarely make panic stops so I do not see this as a big deal. The bigger reason is the brakes may also make a little noise until the pads have made full contact. Again, not a big deal to me. But a lot of people complain loudly if their brakes make noise after a repair.

So my point of view is if you are willing to allow a little more distance in braking and ignore a bit of noise you can just replace pads. But getting a repair place to go along may be difficult. They get paid for their time which will be wasted if you come back complaining and they have to take things apart again. It is your money, not theirs, that gets wasted on the unnecessary parts replacement. By far the safest way for them to go is with new parts.