If they don't have tons of holes or slits in the sides and bottom, as some orchid pots do, I give them to the nursery I work at. They don't sell orchids, but they can reuse most of the pots I give them. It's just a small, local nursery. And of course the regular plant pots that build up go to them too.
I do keep a few pots for myself, to reuse for orchids and the many other plants I have or may acquire. I'm always starting cuttings or seeds of something!
