They usually knock and ask if you would like turn down service. Most of the time I have already ripped off the bedspread and folded down the sheets myself. I usually ask for the mints though. They are always happy to give them to me. I usually get a few extra without asking.

I enjoy turn down service while on vacation because I usually return back to the room mid afternoon and mess things up a bit so it is nice to have a 2nd tidy of the room.