I spent 3 seasons guessing at chain sharpening angles by eye, then a guy in Flagstaff showed me a $12 file guide
Used to burn through a chain a month on my 261 and figured that was just how it went, but since switching to the guide in March I'm still on the same chain and my cuts are way straighter, so I'm curious if anyone else here has a sharpening trick that made them feel dumb for waiting so long.