All blades, knives, and cutters will become dull after a while. And once that happens to paper trimmers, stack cutters, or guillotines, the quality of the work they produce will go down. It can be hard to tell if a drop in performance is because of a dull blade or some kind of mechanical issue. But if you notice that your paper cutter isn’t able to cut through as much as it used to, you most likely have a dull blade. Fortunately, the blades are simple to replace. You just have to remove the safety guard and swap it out.