I am planning on purchasing a used ZTR mower and would like advice. My thinking is I would be better to buy a used commercial model than a new Home Depot residential type mower. I know the lower the hours the better, but what is considered high hours, or how long should one last? I am considering a Toro zmaster, and it has 1200 hours or so on it. Is that high? It is liquid cooled and I have heard they last longer(the engine that is). What should I look for besides obvious things like engine noise, fluid leaks, bearings that are not tight etc.. It is a 2003 with the vacuum system and 60" deck 27 HP Kawasaki. Is around $4k a reasonable price? Also I will probably sell my existing lawn mower. It is a Deutz (same as Simplicity Sunstar, 20 HP Koheler, 60" deck, 850 hours, 1994 model. What could I expect to sell it for?