We keep and breed them. They do live for more than 1 year in captivity, in the wild they don't though apparantly.
I think you can expect a longer lifespan if they are kept correctly, exactly as Glimmerman said. I have also wondered if resting the females every second year would help. Our girl this year clutched twice...4 her first clutch and 3 her second clutch, after that she went in hiding for a while and we didn't see her for a couple of months. I'd daresay it took it out of her. Lately she's been out and about and begging for food again.
They are an awesome lizard to keep...they aren't to be handled though, but are really great to watch in a well setup environment, one of my favourite lizards to keep. The males show really nice colours.