How bad are cheat days?

My example of a cheat day, is at least 1 fattening food for the day. And I used to have a cheat day once a week, but I knocked it down to every 17 days.

Ex of a cheat day... Keep regular diet for the day, but for dinner Ill go out to eat at a resturaunt and get like a bacon cheeseburger, and a dessert; usually ice cream.

Some people recommend it, other people completely disapprove of the idea. Im on the fence with this one. What do you guys do?