This is a very good question.
I love my snakies, but I keep two collections. One is my permenant collection. Ones I don't sell, and the other are snakes, that I got b/c of a trade or had to buy a pair, or this or that. Ones I'm not especially attached to.
Snakes do not bond like cats or dogs, so rehoming them means nothing to them aside from some initial stress from shipping. Okay I don't COMPLETELY agree with this statement, but for the most part yes. They will not pine away like a dog or cat or bird. Regardless I miss a lot of the snakes I sell and am glad that I can sell most to friends I know so I can keep an eye on them and see how they are growing.
Please remember collections evolve, you may pick up this and that species and realize, you REALLY like working with a certain species and not so much the other. It is human nature to concentrate on the one you really like and not interact as much with the one you don't. Is it not better to find another home who will appreciate that species/snake better?
It's easy to say you won't ever sell a reptile when you're collection is under a certain number, but there comes a certain 'magic' number where you have to go, ok, I've got too many. It's easy for that to happen b/c reptiles are just so incredible you can't resist their little faces.