It really depends on the con... I would wait until the con schedule comes out and see if there's anything you'd like to stay for. I stopped going the last day of AX because the Dealer's Hall and video rooms close by 3 and I felt it wasn't worth my time or money to stay an extra day that doesn't even amount to a half of a usual con day for me. I always check the programing though, and the two times they had an event I wanted to attend on the last day I did stay.
"No one has ever written or painted, sculpted, modeled, built, invented, except to get out of hell." -Antonin Artaud