My vote applies to both in-game and in-real-life.

I like the line of thinking; but really, to what end? For example we repair Amour as it wears down do to attrition from battle. Would repairing a piece of property be for some similar reason? For example normal wear and tear over time? That seems excessive. However if there was a cool feature such as arcade style battles for your keep, wave upon wave attacking and you and your buddies defending, I could see repairs after that.