Hourly rate/cost to operate
I ran two years with a 21. The way I looked at it is I dropped my hourly rate knowing my cost was lower then someone with a 10k mower and that I would be less effective. Example takes 1 hour with a 36 would prly take two with a 21. So figure 30 hr rather then 60 either way your making same off that yard. But once again do not tell them your hourly rate give them a price. Then when you get the 36 you can mow it twice as fast for the same price. If that makes sense.