Age

Age was the length of time that a person has lived or a thing has existed, or been alive. Different species could live out lifespans of various lengths, and reach different ages.

Rose Tyler was said to be have been 19 on a poster when she left Earth with the Ninth Doctor and didn't return for a whole year. (TV: Aliens of London) Jackie Tyler celebrated her 40th birthday in February 2007. (TV: Rise of the Cybermen)

Owen Harper died for the first time at only 27 years old. (TV: Dead Man Walking)

The Doctor's age was widely inconsistent. The First Doctor was said to be 450 years old when he regenerated into the Second Doctor. (PROSE: Iceberg) The Seventh Doctor claimed to be 953 years old soon after regenerating, the same age as the Rani, (TV: Time and the Rani) yet by the time of his war incarnation, he claimed to be 400 years younger than his eleventh incarnation, who said he was "1200 and something". (TV: The Day of the Doctor) The Ninth Doctor claimed to be 900 (TV: Aliens of London), with the Tenth Doctor, Eleventh Doctor and Twelfth Doctor all following on from that. The Tenth Doctor claimed that he was 903, 904 and then 906. (TV: Voyage of the Damned, The Day of the Doctor, The End of Time) The Eleventh Doctor claimed that he was 907 a few days after regenerating, then 909, 1103 and then 1200. (TV: Flesh and Stone, The Impossible Astronaut, The Wedding of River Song, A Town Called Mercy) The Twelfth Doctor claimed to be around 2000 on numerous occasions, (TV: Deep Breath, Smile, Extremis) and roughly 1500 years older than his original incarnation. (TV: Twice Upon a Time)