I think the minute you're full up and have had enough to eat, then that's time to retire.

There's nothing like the eureka moment of knocking off a song that didn't exist before - I won't compare it to sex, but it lasts longer.

I did cocaine for about a year around the time of Sgt Pepper. Coke and maybe some grass to balance it out. I was never completely crazy with cocaine. I'd been introduced to it and at first it seemed OK, like anything that's new and stimulating. When you start working your way through it, you start thinking: 'Mmm, this is not so cool an idea,' especially when you start getting those terrible comedowns.

I think the minute you're full up and have had enough to eat, then that's time to retire.

The interesting thing about the Beatles was: The music was one thing, but we kind of symbolized a certain kind of freedom at a time when people of our generation were just growing up and just becoming adults.

Most people don't know that I invented the selfie.

I'm only 49 years old. I'm still in the middle of this whole thing. I don't feel like it's finished at all. I'm still planning to write better songs.