When I change my blades, I put them into another case just like they came in and have a note on the front saying "To be sharpened". Once sharpened I'll use it till it dull again and put it into another case that says "Sharpen for paper". I then use it for cutting anything but fabric until it's not longer decent for paper items. then I put it into another case that says "Dispose" so when it's full it gets tossed safely. I do this for all size blades I use. This way I get as much use out of them as possible. I add a mark on the blade once it's been sharpened once, another mark when it's been sharpened again so I know how many times it's been sharpened. Magic markers work great for this.