We do it to planes and chisels, router bits and knives but few of us sharpen a saw. I'd guess that most of our sawing is done with a bandsaw, "skilsaw" table saw, coping saw and on and on. BUT the first saw most up us used was a hand saw. We all probably have one stashed in the shop to use on the rare occasions that it's just quicker,cleaner, quieter and more suited to the delicate job of making a piece fit just so. But if the saw is dull, watch out! It will wander, tear the wood and perform so badly that it will get stashed in the shop....... the circle just goes on. Here's how to sharpen a saw and make it an essential tool in your arsenal.
http://www.vintagesaws.com/library/primer/sharp.html.