Powerhour!

Got in to a discussion with a friend about our old laptops and its life expectancy, I tried to figure out how to see computer-uptime statistics.
This is the closest I got, its the harddrive power-on hours. (For macs)
http://www.macupdate.com/info.php/id/23777/smartctl


I switched harddrive last fall, so I had 1344 since then… Seems low though.
What’s yours? Or do you know a better way to find out?