Im no pro. I dont have a huge yard, it takes maybe 20-30 minutes to mow completely. I dont over fertilize, so I have a nice grass layer that doesnt grow all that fast most of the year. I bought a flathead B&S craftsman mower in 2006, new. Runs great. Though Ive changed the oil, Ive never touched the blade. I always cut the grass long, to keep weeds out and make it more self-sufficient, so its not like Im hitting roots and rocks, but I can imagine that the blade should get some attention. Can I sharpen it just using a file? How sharp should it be? How do I know when Ive done it enough? Given that I just have the OE blade, is there an "upgrade" I should look into? I dont bag the clippings. Thanks!