I'm a little anal when it comes to cleaning my bike. The chain comes off the bike for a thorough cleaning at least once a week, more in rainy weather. The first chain lasted about 4,000 miles before it needed replacement. The chain on there now should last another 2-3,000 miles at the rate it's wearing now. I have yet to notice any funky shiffting on the cassette, it still has nice clean crisp shifts. At hte next chain replacement, I'll consider a cassette replacement also.