Too Old (or Big) for Trick or Treating?

Most of us, at some point in our lives, have seen a trick or treater and thought, "Now, he knows he's too old for this."

Supporters of little leaguers may give the benefit of doubt, as everyone in the stands has had the experience of questioning the age of a bigger child on the other team.

Let's face it... Some children are just bigger and/or taller than others. Should they be prohibited from enjoying the same things as other children their age, based on size?

Parents, at what age or size do you tell your children they're too old to trick or treat? And at what age do you stop buying costumes, or is there an age for that?