First heard about on screen in 1976′s The Deadly Assassin, the limit supposedly places a maximum of 12 regenerations – 13 lives – on a Time Lord. Since the series return in 2005 and the ever-impending closeness to number 13, speculation has mounted on this; this very site was the first to openly speculate that the limit might have been quashed as a result of the Time War. Not a massive leap of faith when we consider the Master.
According to Steven Moffat at a recent event to promote Doctor Who on BBC America, the matter of regeneration limits has been:
“…addressed in a very, very cheeky way by an old friend of mine and I’m not going to tell you anymore about that,” said Moffat, telling us to “wait and see.”