Yes, chainsaw sharpeners do really work, and make the task of sharpening a chainsaw much easier. Before the invention of chainsaw sharpeners, you would need to individually sharpen each tooth by hand. Now you can use an electric grinder to quickly get your chainsaw back in pristine shape. There are also non-electric options, which require a little more effort to sharpen a chainsaw. Chainsaw sharpeners tend to include a clamp that holds onto the end of the chainsaw bar, where the chain runs around the machine. You need to start the chainsaw so that the teeth can be sharpened as they pass across the grindstone. Grinding the teeth of your chainsaw against a sharpener usually won't take longer than 10 minutes for an electric model. It will take slightly longer with a manual alternative, and you might not get such a good sharpening due to you having to provide the force. However, no matter what type of chainsaw sharpener you opt for, it should work well provided that it is of high enough quality.