the life of a BB? anywhere from 10 miles to 10k. the noise could be lots of things and if you are not handy around bikes I would certainly ask your shop to check it out. do you have 4k on the same chain? that could be causing some noises.
I have a '00 Bianchi with Record and I would be hard pressed to say it has over 2k on it and the BB is kaput! these new sealed units are sometimes (like everything) hit or miss. most BB likes yours might go 10k but if there was a bad ball in the batch yours came from you may have been lucky to get 4k on it.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk