Even custom built monster sharpeners eventually need replacement blades. One can prolong the useful life of a sharpener by swapping blades on the dual hole models. This is due to the fact that one blade will likely get more use than the other. In my classes, the sharpeners are used most heavily for extra thick Prang colored pencils I provide, resulting in the blade for the smaller opening lasting much longer. My first step when encountering a dull blade is to use a screwdriver to switch blades from one hole to the other. I also can’t say enough about the use of premium sharpeners as compared to School Specialty budget versions. Many of the blades originally installed are still going over a year later with no particular maintenance needed.