Also, the Stihl sharpener that Root Cause recommended is excellent. I've done all kinds of sharpening over the years and this thing is not a gimmick. It works amazingly and is fast. For $30 you can't beat but get yourself a bunch of the round files as they dull rapidly if you do a lot of sharpening. My personal rule of thumb is that I run the sharpener after each extended use of the saw; that way it's sharp and ready to go when I next pick it up.