Yes! Sharpen it. I'd noticed a slight vibration and change in the sound of the mower after the last mow. I hit a piece of a root or a 1" stone (or both) and it sounded different after that. I didn't have much left to mow so I went ahead and finished. The blade was somewhat dinged because I hadn't sharpened it since I got the mower, about 9 months ago, but only about 4 months of use plus that last incident. Anyway, I bought a Smith's sharpener and gave it a go on the blade. Took around 30 passes total on each end of the blade and also a little bit with a flat file on the flat side of the blade. I also made sure it was well balanced. But it looks pretty good. Mowed again today and mower is quieter and smoother. Maybe even a bit more suction? It bagged really well.