When I went through The Purge I got rid of about 100 books, but I had already gotten rid of 200 about a year earlier. I kept the books I couldn't bear to give away, either because they were sentimental (given to me by someone), or were personally autographed by the author, or I'm likely to reread or refer to portions of them in the future. They fit into 3 banker's boxes when we moved, and they are now in my compact barrister bookcase.
I have to say if I didn't have an extensive library on Kindle I'd have had a lot more banker's boxes of books.