I have a 99 ML430. My average brake life is about 15k-18k. Presently, My ML430 has 68K, and I have changed 3-4 sets of brakes. My service manager keeps telling me that's average. Is it?

That's sounds about right.

Apparently Mercedes uses a relatively "soft" brake pad. That's also why we have so much brake dust. Some people have switch the pads out to other brands to lower brake dust and extend life.

would the other brands of brakes affect the mercedes brake rotars. I've heard it will wear down the factory rotars faster.

I'm sure it's possible and depends on what you buy. I have read lots of people using porterfields (I think) from ************************ which are not supposed to cause premature wear.

In any case, I've been told that you pretty much swap rotors out every other or every second pad change.

I will never use mercedes OEM brake pads again.. I use "mintex" brake pads, they are made in germany as well.. the oem pads lasted me around 20k, whereas my mintex I'm already driven 20k on them and I still have 60% brake pad left.. Also the brake dust is greatly reduced.. If you can't find them I can send you a set.. I can get them for a good price.. you change the rotors when they are below service spec.. you can search the forum for the minimum service spec..