I made the mistake of putting mint in the garden. It went feral! I've got some in a garden that never gets watered and it's still going mad, so as Maureen said, it's very hard to kill. I don't know of anyone that's killed it from neglect! When I want to use it, I just cut a few leaves off, the nice green ones and leave the rest of the plant go. It always comes back with a vengeance!
Jane