"Pretty much, yeah," the Doctor admitted. "It's kind of like you looking back at how you used to be in primary school, and the stupid things you did."
He fell silent and still, taking the question more seriously than perhaps Bill intended. Too long<'i>, he thought, but he answered, "A single regeneration may live for around 1,000 years, and we get twelve lives, so you do that maths. That is, if they survive to live that long."
Nodding at Bill's observation, he said, "You're quick."