When I first wanted to leave Tayda out of the crate when I wasn't home, i actually set up a little video camera to tape what she did. She wandered around for about 5 minutes, and then went into her crate and hung out in there for most of the time…
Then I got Lenny. I crate them together and they keep each other company. Although I don't think Tayda minded being in there alone. I used to video them together in the crate and even through their crate is big, Lenny tries to sit right next to Tayda or even on top of her and sometimes she lets him know she doesn't like it.
Anyway, I felt bad at first leaving them in the crate when I wasn't home, but after letting them stay loose in the house and seeing that they went to the crate anyway, I just crate them. Its not worth the risk of something happening. Not so much them destroying anything, but the chewing on things that could harm them (electrical cords, etc etc)