I just purchased a Honda Harmony 21" 3 speed push mower last weekend, the kind with the Quadracut dual blades. I've cut two and a half yards with it. One yard had some well-camoflauged corn cob bits (from the surrounding corn field) amongst the taller grass, but the other yard had nothing that would damage the blades. Anyhoo...I started cutting my own yard with it today and noticed that the tips of the grass were turning brown, so I decided I would check to see how dull the blades were. Well, not only were they dull as heck, but there were all kinds of dings in them. It's an awesome mower, but I hate to think that I'm going to have to sharpen twin blades every single time I mow. Any advice from other Harmony owners?