In my experiance from all the mowers we have used, I have noticed that a new ztr or walkbehind will cut like a champ for the first 2-3 months. Then we notice the cut quality will start going down hill. We have noticed this on our lazer z, scag, bobcat and gravely. We make sure the tires have equal air, blades are sharp, and decks are clean. None of this seems to help. Anybody else notice this trend? It baffles me to be honest. We keep all of our mowers in top notch shape. Maybe there is something I am missing. After a while the cuts just dont seem as crisp and sharp. Even with brand new blades.