chains

I think these are fairly simple questions but I'm fairly new to saws. 1. Can I change the existing chain/bar to 20in 72DL .050 3/8, or do I need to replace the rim sprocket a well ? I see there are many more options to buy with the .050 as against my current bar .058 gauge. 2. Whats a good...

I am new at sharpening chains and I am tired of buying new chains just because I do not know how to sharpen a dull chain. Is there any way I could get some pointers on the basic, tried and true method of sharpening a chain? Method used by highly experienced chain saw people. Thanks, Dalton