The revived programme portrays Time Lord children, with a child version of the Doctor appearing in the 2014 episode "Listen". This credit remained from season 19 to season 26. Tom Baker played the Doctor for seven whole seasons which gave the audience enough time to get to know his Doctor well. After many regenerations, Tecteun inducted the Child into a clandestine operative group within the Time Lords known as the Division. She even takes him away to "dance", but how far the metaphor (coined in the episode "The Doctor Dances") is taken is not seen on screen. In "Flesh and Stone" (2010), the Eleventh Doctor tells Amy Pond that he is 907.
Never give up. Davros uses the title "Destroyer of Worlds" to describe the Doctor in "Journey's End" (2008).
 Human companions accompany the Doctor through his adventures who serve as audience surrogate characters to ask questions which allow the Doctor to provide relevant exposition.  Due to the retroactive creation of a numberless War Doctor and the Tenth Doctor's aborted regeneration in "The Stolen Earth"/"Journey's End", the Eleventh Doctor was the final incarnation in his natural cycle.
The classic programme refers to his time at the Academy and his affiliation with the notoriously devious Prydonian chapter of Time Lords.  The following list details the manner of each transition between incarnations: The Doctor's first (Hartnell to Troughton), ninth (Hurt to Eccleston), and thirteenth (Smith to Capaldi) regenerations occur due to natural causes – in all three cases the Doctor shows increasing signs of age, and comments that his body is "wearing a bit thin," though in the First Doctor's case this is apparently exacerbated by the energy drain from Mondas.
In practice, however, since the Doctor stated his age in the Second Doctor serial The Tomb of the Cybermen (1967), his age has been recorded progressively (see below).
Two people who are really crazy about each other..." The narrative of series nine culminated in a three-part story arc in which Clara dies and the Doctor spends the next 4.5 billion years executing a gambit to change history and save her life. In 2013 he returned to Doctor Who for the 50th anniversary special, playing a curator in the National Gallery and also appeared in the series in 2017 to finish a lost episode from 1979. It means remembering everyone I used to be, while stepping forward to embrace everything the Doctor stands for: hope.
In Death of the Doctor, a serial from spin-off programme The Sarah Jane Adventures, the Eleventh Doctor flippantly responds to Clyde Langer that he can regenerate "507" times; writer Russell T. Davies intended this line as a joke. Additionally, Moffat has companion Amy Pond attempt to seduce the Doctor in "Flesh and Stone", although he expresses shock at the idea, protesting that she was human.
Twelve hundred and something I think, unless I'm lying. Drax implies that the Doctor got his doctorate after that.
In "The End of Time" (2009–2010) it is mentioned that after he smote a demon in the 13th century, the residents of a convent called the Doctor the "sainted physician".
In the 2001 BBC Books novel Father Time by Lance Parkin, the Doctor adopts an orphaned Gallifreyan-like alien called Miranda.