Okay, I think I've read everything mowing related ever on this site but this is an area I've not seen discussed (prob. has been though). What would you say the typical life span of a zero turn mower. The guy at my local Deere/Exmark dealer, who i consider a helpful guy, says typical expectations on a commercial ZTR are 4000 hours on the machine, 1600-1800 on the pumps and 2500 on the (gas) engine. I know many of you commercial guys trade these machines more frequently but I would like your input for the sake of discussion. Same questions for walk behinds. Anybody have a ztr with what they consider above average hours on it? I guess I am asking because I am shopping for a used back up ZTR eventually and a walk behind. I know maint history plays a part but whadaya think in general? Any wear items to be particularly watchful for?