Comment by hunterpayne

There is an important point you are missing. Attitudes like this discourage people from doing nice things for others in general. Because you are saying that one nice deed or nice deeds for a period of time mean you are bound to have to do that deed forever for free.

This is the tragedy of the commons but not just for a field of grass, instead its for all human altruism. You really need to think about the consequences of this attitude because it doesn't lead where you seem to think it leads. In fact, it leads to exactly the opposite set of human behaviors.

PS The neighbors could easily just contract someone else to do the shoveling in the future and instead of being salty about having to pay, looking at it as how much money they saved in the past.