I quit at 13. The fun behind it wore off, and for the most part i've just sat at home since. The day means very little to me anymore, my belief that it is something for younger kids to enjoy. That said, i'm pretty sure i remember my sister still going as of last year (14, now 15)... and i have to think that the only reason she isn't going this year is because she's apparently working that night. By the sounds of things, she was intending to wear a bit of a costume to work...

i wouldn't be surprised if the boss had a word or two with her for that. I guess the only reason I don't really complain about her trick or treating is that I could always just meander into her room in the ensuing days, and raid her stash. Whether she liked it or not, if i found it appealing, it was gone... I call this the rite of passage of the older sibling.
Of course now that i'm away at school and can't steal her candy anymore, i don't really care whether she goes or not... funny how that works, isn't it?