Variety is the spice of life.
There is more to sharpening than just knives. Edge tools is the umbrella term I use to include any tool that has a profile for cutting, shaving, or slicing. Scissors, which include hedge clippers and bypass shears for pruning trees, sewing scissors, kitchen scissors, craft scissors or even tin snips all have a similar design and each have a specific purpose. Word of the wise, don't ever use a pair of scissors that belong to someone for which they have purchased for a definite task in mind. For example, never borrow a sewists scissors for cutting paper you may not live to tell about it. Someone used my thread snips to cut a cardboard box and basically left my scissors useless for thread. ( I managed to repair those already). Chisels, planer blades, axes, guillotine paper blades, and drill bits, are just a few more cutting tools you may find in almost household or industrial site and each tool requires a specific technique, cutting angle, and accessory. Although the variety is vast, I have the knowledge that allows me (the sharpener) a quick and efficient way to take a dull lifeless tool and bring it back to the world of sharp metal objects we have come to depend on to get work done.