The o-rings do break from drying out mostly and pulling the tips in/out-in/out, and people use alcohol to clean them which also dries them out, the best thing you can do is put a little coating of Vaseline on them when you first install them and once in a while, just rub it on and wipe off the excess, this will prolong there life span, just a very light coating to make them shine. Home Depot sells Danco Brand o-rings and they have the right size, I forget what it is since its been a while that I've purchased them but something like 6mm OD X 4MM ID or USA = 1/4" OD X 1/8'' ID,, take an old one with you when you go to Home Depot so you can match em up