Originally Posted by dafydd
depends on the quality of the BB and conditions used. i've seen 6-month-old bikes with shot low-end Shimano BBs, and i've heard of Phil Wood BBs lasting more than 20K.
My understanding is that the Phil BB's typically go for 30,000 miles or more. Plus, their bearings are replacable, so the main unit could feasibly go for double or triple that with the bearings replaced. I'm considering getting a Phil BB.