I've got 53+k on the original pads and rotors. The pads are due shortly (5k or less), and we'll see about rotors. This is a stock '04 S430; 17" wheels, 225x55 tires. I don't know if I am a "moderate" or "easy" driver--I push the car left and right, but don't use the brakes hard much at all. It's that Bondurant experience, I guess--when you scrub off speed with the brakes, you lose the exit speed. Around town I don't go the "stop light slam-it-on-slam-it-off." That may be why I average 22 mpg.
I performed the service II on my 2004 S 500, and they are supposed to check for rotors and pad thickness, and advise you to avoid replacing expensive rotors if the pads are worn to the point where you are braking with the rotors. You second check is the actual worn pads indicators. Nothing was mentioned on the "soup to nuts" service II maintenance.
Three weeks went by and the worn pads light came on, next day I took the car to have them replaced, and received a call from the service adviser that the front rotors and pads, and I quote "were fried" and needed replacement $ 790.00. I asked whatever happened to the pro-active maintenance to ferret out these issues, and could they provide me the actual thickness of the rotors, and pads; a required part of the service II.
They were unable to provide me with the information, I had to speak to the service manager and MB USA to have them pickup the cost since it was their mistake not to check for break wear three weeks prior, and only after one day of brake pads light diagnostic light blinked, and the rotors got fried.
Then they tried to back peddle on a junior technician that made the mistake that the rotors were "fried". I called MB USA and eventually the sleaze dealer who wanted to screw me on replacing good rotors, had to eat the cost to install new ones, and I did request to please retain the old ones to see how fried they were. Unfortunately, someone did not get my request and were tossed away; environmental hazard you know.