I very rarely buy physical books as presents or if they are craft books or have a lot of maps. Estimated books bought per year are four or five. All these books are second hand, even those I give as gifts. I have a really small shelf with craft, cook and fashion photography books.
But I don't buy more than that as ebooks either. Most of my reading material comes from the public library. I am a patron of two to four libraries (this changes with their acquisition strategies) and I spend between 6€ and 30€ per year on it.
I sold most of my physical books over a decade ago to buy my first ereader. I kept the most loved and beautiful books because I wasn't sure I'd take to the reader. When I realized I would never go back to paper, I either sold or donated the rest of my books. And I was fed up with dusting the damned things off anyway.
There are companies buying used books to sell them on Amazon Marketplace or ebay. They have websites and one can scan the barcode of the book one wants to sell, to find out how much they offer for it or if they don't want it at all. I did that for the majority of my home library, which was HUGE. For the donations i contacted a project that offers books for people in a not so well off part of the city and they came to my house and took what they wanted. The rest went to booksharing places in old telephone booths.
The money i got for my books was shockingly little. Sometimes 0,10€ for a premium book, still on the bestselling list I had paid 36€ for myself. But I told myself, they'd wouldn't earn me anything sitting on my shelves and gathering dust. The money was gone and I actually couldn't loose, just gain some of it back. And in the end there were some books that had some value and the amount I got all in all wasn't bad at all.
One totally unexpected benefit of getting rid of my library was getting rid of the dumb "Have you read all these?" question. "No, silly, I bought them for show! Much better than having a sports car or a yacht to impress people!"

This alone is worth it!
Since I got my first reader I haven't read a physical book. I might peruse them, like cook books, but I haven't read the books I do read front to back other than on a reader. Last week an acquaintance wanted to gift me the book they just wrote and I said, if you want me to read it, send me the ebook.