It's so hard to get rid of books, especially when they are nice and new and haven't been read much, when my six copies of Stormbreaker are all held together with duct tape and I glue a two foot stack of books back together each week! (Or volunteers do! Thank you!)
There are reasons books stay pristine. Read one last night that had a dopey cover, silly title, and a description that didn't make me want to read it. I showed it to all three of my children and got the same reaction-- that slight, almost imperceptible nose wrinkle. Now, if I read a book and discover it has merits, by all means, I keep it. But this poor, unfortunate book didn't. So it is going to a better place where it will be happier. After 20 years, it should have gone out more than 8 times.
The publishers are doing a good job making cover art more timeless. Now if they could just make books where the pages don't separate entirely from the cover!