I sharpen my lawn mower (ZTR) blades with my 4" angle grinder; don't balance them but once a season.
The original 2002 blades lasted until 2023 cutting 1.5A. I don't mow rocks or sticks so the blade ends stay relatively square. Sharpening istructions say to sharpen the tip if it get rounded, as the rounded edge cuts too.
One of the hardest things on a nice lawn is to mow with dull blades. Instead of a clean cut, dull blades rip grass, which stunts the plants; stunting allows weed growth to out-pace grass growth, as does cutting grass to less than 4" high.