To steal the shells for bigger homes to try out, they often don't even take them. Hermits can be a P.I.T.A. that way. I get the small red and blue leg hermits (about 1/2") and add some larger shells for them to find (which doesn't always work). When they get too big I take them to the lfs or give them away and get new small ones. Turbos are great, astreas, margaritas, and bumblebee snails are great cleaners, although small but they are pretty cool looking too. You will also want to make sure you get some sand sifting snails as well if you have a sand/gravel bed. they help to stir up the detrus which is important. (the hermits will have a field day on these small guys though).