DOCTOR: Some people live more in 20 years than others do in 80. It’s not the time that matters, it’s the person.

DOCTOR: I’m old enough to know that a longer life isn’t always a better one. In the end, you just get tired; tired of the struggle, tired of losing everyone that matters to you, tired of watching everything you love turn to dust. If you live long enough, Lazarus, the only certainty left is that you’ll end up alone.

DOCTOR: if you live long enough, Lazarus, the only certainty left is that you'll end up alone.

LAZARUS: That's a price worth paying.

DOCTOR: Is it?