Is a good metal file worth the money, or would Home Depot's most expensive file suffice? I mainly need to sharpen my lawnmower blade, but I'm sure I'll use it for other random tasks (i.e. sharpening other woodworking tools).
I looked at the the $10-15 ones at Home Depot (and Ace hardware) and they seemed decent, but this is something I'll have for life, maybe it's worth spending twice that amount for a nice one.
Would a flat 8" or 10" work best for sharpening lawnmower blades? If you would recommend a nice one, where would I get it (Lee Valley, Rockler, etc)? Any recommended brands?