I am fairly new to the commercial side of lawn cutting. I have run a property preservation business for several years and am just recently getting my lawn cutting to a more professional level. Before this we didn't have that much so it was basically taken care of by our normal contractors with their own lawn mowers (usually a POS push they got at the local pawn shop). But we now have enough that my wife is going to be taking care of it. I bought her a 2008 john deere 657a to use. My concern is that these lawns are often times pretty bad, they can be 1 to 2' tall and the yards often have lots of stuff to hit (rocks, stumps, logs) that you don't see until you have hit them. Other then changing the oil more often (because of the extra strain on the engine) and sharpening blades a couple times a week is there anything I should be doing to keep the mower running tip top?