De-cluttering books

I loved this series from the Washington Post about how this poor woman set about de-cluttering her attic, which from the photos looks like it was a complete wreck. So over the course of 11 weeks, I got to read a different aspect of how to de-clutter.
Week 4 was -- you guessed it -- de-cluttering books. I eagerly read the installment, because my shelves are overstuffed and unsightly. Alas, the author wrote:

On the issue of books I got surprisingly little help from Caitlin Shear, the professional organizer who has signed on to be my coach and hand holder during this process. Each week she has led me through the sorting, scrapping and separation anxiety of dealing with clutter. But when it comes to books, fiction and nonfiction, she is unabashedly a keeper.

"I am a big books person," she admits. "I tend to get rid of everything else before I will let go of a book." She has even allowed her husband, Mike, to keep his collection of science-fiction paperbacks from the early 1980s. "I am," she says, "a total bibliophile."

So this was not very helpful.

I will soon be turning to lessons learned from my recent library science class on Collection Development, on what librarians call "weeding." Weeding is when a librarian from time to time discards books that have been little used or are worn out. Yes, they discard them, and that means they throw them away, though sometimes the books go to reading programs etc. This is done because no one library can hold every book, and shelf space is at a premium.
I'm going to try really hard this weekend to weed my books and maybe even sort them.
What are the criteria for weeding, you ask? Well, poor physical condition is probably the number one reason, followed by outdated information and/or lack of patron interest. Wish me luck because I weed my books regularly and it is very difficult to find things to discard.