I can’t speak for post January E53’s. But my pre February 2002 X rotors were turned, and were still well within spec. I’m still running the original rotors at 99,000 miles, with no issues, and still in spec.

Regular brake fluid flushes though, every three years or so. Do not use cheap fluid, use the appropriate spec.

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02 BMW 5 Speed Supercharged Ethanol Burnin Meth Injected E53