It's not unusual for even the best TV shows to hang on past their freshness date--sorry, ''Simpsons.'' We pinpoint when it and some other faves could have quit, uh, heroically, from ''Heroes'' to (we'll say it) ''The Wire''
The Ideal End: Not every show can reinvent itself and still hang in there like Weeds. Throughout its run, Nancy Botwin burned down suburbs, traversed borders, and served time. But as the question changed from how she would escape her latest mess to why she was still in it at all, the time had come to call it quits. The end of season 6 was the perfect window: In a thrilling finale, Nancy escaped death and protected her family by turning herself in at the last minute.
Badness Avoided: The season 6 finale made up for an aimless plot that followed the fugitive Botwins on the run. Though season 7 was an improvement, largely because the show returned to some of its roots drug gang rivalries, Heylia's return Nancy became harder to root for, and the plot twists were too easily resolved. Nolan Feeney
Image Credit: Jordin Althaus/Showtime