To sell or not to sell?

What to do--I want to add to my doll collection, but I do not have the space.  I currently have storage issues, and it kills me to have any of the dolls in boxes.  So what to do?  Sell a few?  But how do I decide which ones to sell and which to keep?  Ack!

I have heard from another collector who rotates her dolls every month and season.  That could be an idea.  I should perhaps consider this as an option.  Or perhaps moving some of my books out of the way and making more space for the dolls.  We'll see.  I can be creative here.  Maybe a bigger house?