who is to say that this is the doctors' tenth regeneration? hes had ten since the sixties but he's meant to be 903 years old, also countin films, 12 actors have actually played him.

i also always wondered whether 13 regeneratins were all a time world could physically do, from his own natural ability or whether that was a restriction or gift? set by the time lord society, didn't the master say in an earlier series that he had been brought back by the timelords and given a second span of 13 lives?

it could be now that time lord society is gone the doctor is free to regenrate as many times as he wants.

its a mystery!
its never been explained properly so who knows? i think there'll be more regenerations!

I agree its never been explained properly so i would not know but you have to think if the show is going great, with great ratings etc in say six years then they are going to think of 'some lame way' to extend it though if the show is doing badly then they are just going to say hey lets end this maybe leave it open ended so that they can come back to it if need be. SO i would not really know :D

It's true that the series never explicitly stated that the William Hartnell Doctor was the first incarnation, though the BBC has been pretty supportive of the idea of numbering them as 1 - 10. The films with Peter Cushing all also portrayed the first Doctor, though, so you can't say that those were separate regenerations. I'm curious as to your count, though: are we thinking the same person as the twelfth actor? I know William Hartnell and Peter Cushing (1st Doctor), Patrick Troughton (2nd), Jon Pertwee (3rd), Tom Baker (4th), Peter Davison (5th ), Colin Baker (6th), Sylvester McCoy (7th), Paul McGann (8th), Christopher Eccleston (9th), and David Tennant (10th). That's eleven. Who's your twelfth? I suppose you're counting Richard Hurndall from "The Five Doctors", also portraying the first Doctor?

Also, "The Keeper of Traken" was pretty explicit in explaining how regeneration worked, wasn't it? It's a biological limitation on the Time Lord's regenerations. Extending life beyond that last regeneration takes something akin to necromancy - essentially what the Master has done.

no that was a mistake