So I had my bike in for a tune-up last week, and the mech let me know that the BB was pitted and was going to need replacing soon (~1000km). Since the part ordering was going to add another week to my off-bike time (I know, I need a backup), not to mention I was already installing a new chain and cassette, I passed.

My question is: how do I know when it actually needs replacing? Furthermore, is running a pitted BB going to cause any knock-on damage to any of my other components? Is there a sound I should be looking out for, or will I just notice a degradation in performance? I have a LBS which doesn't need to order the part, am I better off just picking it up and doing the install now?

Thanks for your wisdom.