I figure the jockey wheels on my derailer will last nearly forever, but what about the rest: cassette, chainrings, and chain? How many miles, kilometers, or furlongs do they normally last?
I know that there are definite signs of worn out sprockets—what sort of mileage is typical before the point where the wear is significant enough to require replacement?
This is for a commuter/touring bike with Shimano 105 components that is reasonably well maintained. I clean & lubricate the chain every few weeks.