One of our bathroom taps destroys its washers. The other three are fine, but this one hot tap has to be closed so tightly that after just a few weeks the washer (standard flat half inch) breaks, leaving a small disc and a separate outer ring. It must be something to do with the seating in the base of the tap because I've swapped the top with its neighbouring cold tap, and that made no difference.
Would using a reseating tool on it help?