Well, I have an Olfa cutter and mat of which I have had appx. 22yrs. Only this least year a quilting friend from Okla. ask me about changing my blade and I said: Huh, dada what for? She explained I needed to so I did but it seemed to work the same. She then gave me a bigger cutter which I sure do appreciate greatly for cutting all those layers. My #2 cutter still has the same blade in it and it still works ok. (I used it for upholestry and vinyl and decided I needed one just for fabric so bought another of the same years ago.) I have no idea except the new blades are a bit lighter I noticed. That may make a difference; probably does? not sure?