Summary: Two thousand years! That's how old The Doctor is now, as stated by the Twelfth in the latest trailer and as implied in his predecessor's swan song, "The Time of the Doctor." That's a pretty huge leap from roughly 900 years old at the start of Steven Moffat's showrunnership. Is it a fair leap when you consider the assumed ages of his predecessors? Or is "fairness" even a fair issue?
