Very seldom, and in general it's not needed anyway. It was just another waste of time.
I did play in one totally-in-dungeon game. Myself and this other guy were the mappers. We mapped everything. And we were darn good at it. Then about, oh, nine or ten sessions in, we are about to link up to a portion we'd been to before... and the tunnels don't match up. We go back over everything and finally realize that what we thought was maybe two levels was, due to a teleporting/elevator room, probably four or five levels with countless passages we had not been down in our search for the Thing We Needed To Leave The Dungeon. All our hard work had been for nothing. We took the twenty or so sheets of graph paper and tossed them on the DM's living room fire, and never bothered with it again.