I got 85k miles out of my first 2 sets of stock brakes which inluded 3 or 4 track days. I can't gauge my current brakes because I installed a set of Hawk hybrids in November and after my second track day on them on Friday, I had to do an emergency brake change on the fronts because I was down to the squealers after my 3rd session. It probably equated to about 12k miles
