The forthought of having a couple pre sharpened chains for each saw in the tool box paid off the other day...dying spice tree and a ding in the dirt accounted for one, then a nail in a pittosporum accounted for the second, but having them to hand to swap out looked professional to the HO, he was even very apologetic and worried about the equipment, I could have added the price of a chain...but I didn't.
10* up or 10* down...for stihl chains the former removes excessive hook and the latter adds more hook, especially as the cutter gets shorter, otherwise 90* if all is well.
I confess to using a guide, just never got out of the habit...got to try freehand sometime, see what I can achieve.
Always use a handle, how many people bang a wooden handle on top of the top plate after sharpening to knock off any burrs? I was taught to do it originally, but then later told it doesn't matter, but that was in the UK where the majority of wood we were cutting was soft...I think if I can feel a burr on the top or side plate, i'm going to spend a few extra seconds to tap them off the top and rub around the side with a wooden handle.