Dull blades can actually kill the grass, or rather, they tear the grass instead of cutting it, and that jagged torn edge of the grass blades is like an open wound and is suseptible to all types of fungi and grass diseases. Unless you want to have to sod or overseed every year, keeping the blades sharp will help prevent your grass covered campground that's a nice place to camp from becoming a mudhole no one wants to camp in. They don't have to be razor sharp, just reasonably sharp. Sharpening even 3 or 4 times a season will not neccessarily mean you have to replace them every year, it just depends on how badly they get banged up and how much metal you have to remove to get them sharp again. Do a search on the forum for blade sharpening. You'll find posts from people that leave an as bought edge on their blades through the spectrum to ones that get them razor sharp, it a personal choice, but leaving a slight blunt edge is probably best for longevity of the blade. Just be sure they're balanced well also. An out of balance blade causes vibration that will eventually wear out bearings on spindle shafts.
