Dave, when you start feeling that your collection is taking up to much space or costing to much it is an indication to get rid of some of your collected items, in the best case by selling.
But you shouldn't do stuff away just to collect the same or similar material again.

It is exciting to get boxes of discarded games and stuff, and I do recommend going through these for things you really want but your home shouldn't become some kind of dumping place for people's old home computers and software because they know they can probably get it rid off with you.

Earlier this year I did away with a lot of old PC games I knew I would never play or even sell as there would be no one interested in it these any more, despite the good conditions I kept them in.
I gave them to a store that sells goods for money that is used for humanitarian aid in third world countries.