This doesn't really apply to me as I love window cleaning and don't mind doing it for a minimum profit and even a loss some times.
But on a serious note, if you were a normal person and didn't like window cleaning, how much would you expect to make per month to avoid the temptation of getting a normal job?
The reason I ask is that one of my old employees has now gone to work for himself and he didn't seem to like window cleaning much either but he is trying his hand in the window cleaning self employed game.