Saw blades are expensive so it's worth your wallet to make sure they last as long as possible. Many times when a blade seems to be getting dull, it can be brought back to life without resorting to having the blade sharpened. Often blades get dull not due to dullness of the cutting surface, but rather due to dullness caused by a buildup of pitch (wood sap) on the cutting surface. To revitalize the saw blade, all you need to do is to remove the pitch.

There are a variety of products out there that will remove the pitch from saw blades. I use simple green myself. You just soak the blade in a diluted mixture (1:4 is what I use) for an hour or so and when you are done, you have a saw blade that cuts like new for a fraction of the price.