I try to buy nearly all my new books that I buy on the Kindle - the exceptions are books that aren't published by Kindle and I collect Persephones and Virago Modern Classics - some of both are now available on the Kindle. I also still have too many paper books coming into the house and I ran out of space a long time ago, we put up a garden shed to make room for DS1 to move into his room, which DS2 now shares, but there's still a problem.
I get quite review copies and library books on paper, and I buy secondhand books. If Kindle books come up free or at 99p, I will get ones I already own and try to pass on some of the paper copies.
If you find you don't really use it, perhaps you should sell it or give it to someone who will, I don't know if those who hate theirs and those who want one could come to a deal here.