To keep my cutters uniform and meticulusly sharp after a few hours use I mount my chainsaw when home in a vice at a level my eyes focus very well on the cutter and I file around 1 or more times until all are even and sharp. I gauge my tooth size with different size screw drivers, suppose there are better gauges, but my screwdrivers are handy. Use my eyes to make the gullets look even and hit the drags evenly a bit now and then. Sharp files make it easy to keep things even,and it doesn't waste time and physical effort taking to long, I discard dull files. If I feel my saw cutting speed slowing up while working, or suspect it will from the cutting conditions , I will touch them up usually at refilling time or switch to another chainsaw as needed to keep going with a nice sharp chain. I carry extra chains and bars in my truck, once in a while I do some switching, but with usually 3 or more saws in the truck, I switch saws. I hate using a 1/2 sharp chain or less, to much work, harder on the operator and the chainsaw itself.
I also try to miss dirt or debark with an axe if my cut is where dirt is present.
I do use a grinder now and then on badly dulled chains or chains that pile up on me not on saws, being careful not to overheat them which usually requires going around multiple times on other then touch ups.