I thouhg my old disposer baffle was fine, except that it would build up a lot of "goo" every few days even though I didn't use the disposer much.  The new baffle does not have this issue, I am finding (hence, finally threw out the 10 year-old version). These are made to be resistant to bacterial growth - but I am guessing this breaks down as well as the rubber (creating microspaces for good to stick). So a new baffle was a small treat to make my life better -and a great bargain!