DS Daily: When is it enough?

Since we've got awesome new details on Mario & Luigi 3 to digest on, we've been thinking sequels. They're nothing new and the idea of the sequel isn't going anywhere. But, when does a franchise just overstay its welcome? Any franchises you think need a reboot or should just plain go away? When do you find a series has lost what it so great in the first place? We're looking examples here, people. Oh, and with this being such a broad topic, it's okay if you talk about non-DS games. We'll allow it just this once.