500k is about a week and half for me. Sometimes I can get close to that in one week. They were a cheap OEM no name model that came with the bike and they sucked. The caliper actually died on me at the end - the threads stripped. Perhaps good quality mechanical brakes are just as good, but I like my Shimano Hydros MUCH better. They never give me any trouble at all. Though at 7000km the are starting to show some wear on the pads.