Brake Disc Rotor problems of the 2006 Lexus IS250

In November 2006 I purchased a new Lexus Is250. I have taken it to a Lexus dealer for all scheduled maintenance. The last time they rotated the tires. Right after that I noticed a 'noise' with the brakes. At the next service (22,500 mi) they are telling me that the rotors have to be replaced and that I should expect that again in 20,000 miles. I am not an aggressive driver. I had my last car (mercedes) for 10+ years with zero problems with rotors. This seems unreasonable on a new car.

I bought my new car a Is250 Lexus on oct 26, 2005. After 11k miles or so, my brake makes loud and consistent squeaking noise. I talked to the dealer and manufacturer many times, but they failed to resolve the issue, and state that it's normal. I think this is very serious for consumer, because it might fail someday and we don't even know it, but Lexus continue to refuse to fix the problems by saying it's normal for such car. As for the issue, I think it's life threatening for what it is use for.