I have had mine for about 8 years and average about 6 events / year so at about the same 50 race weekends as you are. I as well have done nothing except bleed fluid and swap rotors. I am on my 3rd set of rotors but have changed out all previous pairs for preventative reasons.

The only issue I have seen others have is the hardware elongating the holes on the ring. I have seen this in a previous set of mine as well but did not have a failure.