A now having finally finished setting my place set up, I couldn't be happier with having a smaller collection. I bought one more record cabinet for a cylinder phonograph. Now I occupied all the available space; and have a smaller collection that I can easily use each machine routinely. And it gave me some extra money to find decorations for the wall that would compliment the collection. I recently found a pair of 4 wall sconces from 1935 on facebook for $20. Re-wired them and now have them on the walls next to the phonographs! It almost feels like an authentic experience being in here now.
To answer the question: "What do we do when we run out of space?" I'd say: Let go of the ones that you don't use to make room for ones you will. I say it's better to have a smaller, unique collection; than a huge collection of common items. And if the collection was already whittled down and something is being added.... somehow *just* enough space magically appears somewhere

David