I think I stopped when I was 13 - mostly because my friends were less interested in getting candy than hitting everyone else with shaving cream, and since I was a "big kid" and one of their friends I got nailed and they ruined my costume.
I'd probably still be trick-or-treating if they hadn't done that.
I'm excited because my neighbor downstairs is in 3rd grade, and he's not going trick-or-treating beyond this block of our street, so live-in and I are going to do a reverse trick-or-treat with lots of goodies.
His dad is going to loooooooooooove us.