Goodness I don't keep a mat that I use for more then two years. I like cutting on a new mat. I have had many brands of mats and I don't have a favorite. They all do the same job while new. When they get cuts, they get dull just like a blade. Self healing doesn't mean no cuts are there. I have the large table covering mat and use a mat on top of that and many times a smaller mat on top of that one. I choose my mats according to the size of the cut I'm making.