I bought my lawn equipment as a combo package, without doing enough research . The mower that came with it is a Gravely 52" HVZ rider residential edition with a 23hp Kohler engine. Seeing as I only have 8 clients(averaging 1/4 acre or less, I dont think i'm over working it. I just purchased a 32" Exmark WB, 15hp Kawi. I took it to a dealer and had everything fixed(new tranny, pull cord, etc.). I will be using this as a back-up and to get through gates. The gravely dealer says the engine is the same that is used on the commercial edition. So what is the difference in commercail and residential? Also whats the life span on this mower with doing the proper maintainence?