Originally Posted by
ThermionicScott
So, dumb question: I've got a couple of spare Shimano cartridge BBs in boxes since I hate being without a replacement part when I need one -- should I twist them once a year, or every couple of years, or is it really only a concern if a part goes unused for 20 years?
As a guideline, SKF specifies a shelf life of three years for their sealed bearings. I imagine other manufacturers' shelf lives are similar. Consequently, I'd be exercising the bearings to stir up the grease at intervals no longer than that, to ensure you get maximum life expectancy.