Paul McCartney is still hungry for success after remaining at the top of the music industry for 50 years.
The former Beatles singer said stars should always think about somebody who might be better than them, Daily Mirror reported.
"It seems to me that no matter how famous, no matter how accomplished or how many awards you get, you're always still thinking there's somebody out there who's better than you.
"I'm often reading a magazine and hearing about someone's new record and I think, 'Oh, boy, that's gonna be better than me'. It's a very common thing. One thing that's good about it is, I think it's a good motivator. It keeps you hungry. I think the minute you're full up and have had enough to eat, then that's time to retire," he said.
Paul, 71, revealed the song 'Early Days' on his latest album 'New' was an attempt to set the record straight about his early life with John Lennon.
"So many times, I will have people tell me what I did when I was younger. There's so much being written (about) the early Beatles period, and even pre-Beatles period.
"And people will say, 'Oh, he did that because that, and that happened because of that'. And I'll be reading and think, 'Well, that didn't happen' and 'That's not why I did that'. I was remembering John and I in Liverpool as young boys, walking down the street, dressed in black, guitars slung across our backs, trying to get people to listen to our music.