i never remove chain to sharpen
I always sharpen my chains on the bar and they do really well. I don't know how well they would pass a scientific measurement test, but my test is - does it throw chips? I touch the chain up with 4 strokes of a file on each link every time I refuel and my saws stay very aggressive.
When I see dust in spite of the sharpening I make 4 strokes on each raker - never bother with a depth guage.
I am sure I could squeeze a little more efficiency out of the chain, but this approach takes 5 minutes (18" bar) and can be done anywhere. I have a stump vise to hold the bar steady that I use about 1/2 the time.
Remember, a dull chain puts unreasonable wear on your saw (and body) and creates a higher risk of kickback. Better to keep a chain close to 80-90% sharp all the time than to let it degrade significantly (say to 50%) then bring it up to 95%. You spend too much time cutting with a chain in a dangerous state. The only way around taht is to hit it each tank of gas or swap chains regularly.