What I do is hand file a stroke or two after every 2nd fuel refill.
Makes a word of difference and generates nice long chips with fast cutting.
Only if I nick on stone or sand do I resort to mechanical grinding.
I also like to keep my files dry and clean for maximum performance.
Rust dulls them and oily files simply don't perform well.
On the other hand a well treated file really extends a pricey chain's life.
LOL, I got lucky 3-4 years back and bought a couple doz files at a yard sale for $1.00 each. Good quality to boot!.
I do have an 'el cheepo' electric grinder for those really mangled chains that need a real tune up but rarely use it.
Must add that occasional trimming of the rakers is as important as touching up the teeth. For that you want a 10-12" single cut mill bastard file, couple of strokes every now and then, not too much as you will take a bigger bite than your saw can handle.
Another thing to consider is that soaking your spare chains in oil is a good thing to preserve them. (bagging them in plastic with an ounce or two of oil is good)
