[BlueAbyss]

I won't vote because it's not that cut and dried... As Dolf mentioned, while they are there on the natural reef, they aren't required in a reef tank and certainly not in the numbers that many LFS would have you believe you need. I say if you like them most definitely go ahead and get a few, but don't overdo it. They also vary in reef-safeness between species and even individuals, so do some research ahead of time... I had a little Blue Legged Hermit and found him to be an interesting, benign creature, I'd recommend getting several of those if you have a large tank.

Also, if you have whorled-shelled snails like Nassarius and the like, I would seriously avoid hermits in general since they like to kill snails to take their shells (and eat their bodies). Though for the time I had my hermit, he never touched any of my Stomatella and Colonista snails. That I saw, anyhow.

Hope this helps!