I am just starting out. I used to cut grass as a teenager (mid to late 1980's) when the sight of a work crews, trailers and ztr mowers were not a common occurence in my home town. I also have a little over two years experience on a nine hole golf course and was an assistant greens keeper for 1 1/2 of those years. I would like some comments and advice on the following equipment information i have aquired. Concerning riding mowers: I have the understanding that with proper on time maintenance a commercial mower should last approximately 8 to 10 years. This information came from several lawncare professionals who had employed several work crews so i am assuming the equipment they were refering to was operated by several different individuals over that 8 to 10 year period. If one piece of equipment is operated by one or two (equipment conscious) individuals over the 8 to 10 year period as opposed to numerous operators it should be expected to last longer. I wonder how much longer. Considering the aforementioned information (concerning the 8 to 10 years) would the equipment most likely have been a diesel or a gasoline engine. Shouldnt a diesel engine be expected to have an approximately 45% longer mechanical lifespan than a gasoline engine. Would it be practical to spend up to approximately 40% to 45% of the original equipment cost in repairs before considering the purchase of a new piece of equipment. Concerning walk behind mowers: Providing proper on time maintenance is performed shouldnt an individual be able to replace the original engine once on a walk behind before the other parts of the mower are worn out beyond repair. Would it be practical to spend up to approximately 40% to 45% of the original equipment cost before considering the purchase of a new walk behind. JUST IN CASE IVE FORGOTTEN OR MISSED SOMETHING what are the pro's and con's of diesel verses gasoline in lawn equipment.