Up until Rocky was about 15 months old, he used to be in the crate about 8 hours a day but it was broken up by my lunch hour. At about 15 months I started letting him stay out of the crate a half day here and there. Then I built up to a day here and there. Then several days at a time until I finally stopped crating him altogether at about 18 months. In the last six months he's been crated only on rare occasions.
That said, I realize I have been very lucky. He went through a few destructive streaks early on but now seems to sleep most of the day while I'm away. When I get home for lunch he's stretching and yawning but ready to play. When I get home in the evening, he's ready to burn some energy. Then he's wide open till bedtime.
He still chews on my rug in the living room sometimes - he shredded the side on one of his wild streaks and I figured I'd just leave it until he gets a little older and hopefully calmer. Now he really doesn't tear it up, he just pulls the corner up. He chewed on my coffee table and window seal within a week of each other but again, he only did this once while he was adjusting to "freedom". Now he generally leaves everything alone. I know one day I may come home to some redesigned furniture but so far I've been lucky and I feel much better knowing he can walk around, etc.