Metallica just keep rocking along, year after year, becoming one of metal's most enduring acts. But with that longevity comes the possibility of complacency, which is something that drummer Lars Ulrich says he doesn't think will ever happen.

The drummer tells Metal Hammer that the band's drive and ambition will keep them from ever breaking up, as long as they're fit enough to keep on going. He explains, "I don't think I'll ever be bored of being in Metallica. I think that one of two things can happen. One, is the physicality of what we do -- if we don't have the strength to do it physically anymore. We will always have the strength to do it mentally, so I'm not worried about that. But if there ever comes a time when we feel that it's not going on all 12 cylinders, then I hope that we have the guts to walk away from it."

Ulrich says the other thing that could happen is the evolution of outside interests. He ponders, "Is there a chance that when I'm 55, I'll want to write a movie? Or that James Hetfield will want to make a country record? Or that Kirk Hammett will want to go surfing for a year?" While that is a possibility, Ulrich says he feels the band members will always find their way back to Metallica.

He adds, "I don't think I'll ever wake up and go, 'I'm bored of being in Metallica,' because of the nature of who we are as people and the dynamics in our personalities. We always make it interesting for ourselves. That's why we do crazy s--- like 'Some Kind of Monster' and the 3D movies. We throw ourselves these challenges. It's to make sure that boredom never sets in."

When asked what he thinks his 18-year-old self would think about what he's doing now, the drummer explained, "I think he'd think that he's alright. He does a pretty good job of keeping it real and dealing with all the things he does. I realized that I say one phrase quite often: 'I'm doing the best I can.' I think the 18-year-old would look at the 48-year-old and go, 'He's doing the best he can.'"

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