I'm not completely up on Who history; but as I understand it, the Doctor has 13 regenerations. We are now at Doctor 11...or is it really 12? To regenerate, you must have generated first; so if Hartnell was the first regeneration, then there should be a Doctor Prime that he came from. Right?
Smith is the 10th Regeneration, 11th Doctor. The doctor has 13 lives, 12 Regenerations. Though, if ratings are still favorable, the Showrunner will either ignore this piece of canon or write him more lives (Sarahjane Adventures already had a throwaway line that he had over 500 lives, which may or may not have been serious)
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?