Los Angeles - Charlize Theron isn't worried about career longevity.
The Young Adult star admitted she has no idea how long she will remain an actress for but says it is the uncertainty of her profession that makes it interesting.
She told Los Angeles Confidential magazine: "I don't know if I feel I'm here to stay, but that's a good thing. That keeps you on your toes. I think this is an industry where you can't get too comfortable.
"It's constantly churning with great talent, and you've got to raise the bar and try to push yourself. I don't ever want to kind of feel, 'Yeah, I'm here. I made it.' I think that would probably be the time to retire."
Charlize also credited her Oscar winning career to her "tenacity", revealing she doesn't "half ass anything".
She explained: "There's a great tenacity when I tackle something, and I don't half ass anything. When I work, I work really, really hard. And I think that - combined with the people who believe in me - has been really a great blessing."