"Remind me, what is the life expectancy for a Time Lord?" You asked.

The Doctor frowned, still staring down at the tea in front of him.

“A Time Lord can only live for about 12 regenerations. Lifespan of regenerations vary, though, based on if you take risks or not. They can be billions of years, if you're careful.” "Yeah, I think you'll be fine." “Oh, shut up. I’m almost done with my first millennium, and I don't exactly expect for that billions of years thing to happen to me.” "I've only got sixty more years, give or take." You said somberly.

He froze, suddenly looking up at you, his earlier smile gone. You had only sixty more measly years, give or take. He’d often forgotten that you humans had such a short life expectancy. He’d come to terms with the fact that people were human, that they all died eventually, but 60 years? That was nothing. That was far too little.

"And I'll get old, and gross before I know it." You sighed. "But I don't like thinking about that."

His head was spinning; his hearts were aching. You were so young, much too young, and your life wouldn’t even come close to a fraction of his.

“You're certainly not gross, Samantha.” He assured, his mind still reeling. “You’re beautiful.”