I'm able to get good results with just a round file of the correct size, a flat file, and a raker gage. I'm slow, but I'm a perfectionist so it takes me 10 to 15 minutes to hand file an 18" .325 pitch or 20" 3/8" pitch chain. (They have the same number of teeth.) I also sharpen 3/8" LP chain. It's so easy and the results are good enough that I couldn't see myself taking it in to have someone else sharpen them or buying a new chain before the old is worn out. (Not counting buying spares.)