Comment by wakawaka28

What you are saying is especially true for fiction, less so for nonfiction. Many nonfiction topics are important and require a large volume of materials to remain as reference. For example, you never know when it might be important to know how something was manufactured 50 years ago, or what happened in Congress 20 years ago, or what a newspaper reported a hundred years ago. This makes it really hard to judge which items could be culled. I'm inclined to agree that borrow rates are relevant but they are not the only thing that matters. The possibilities of digitization and interlibrary loan make culling less risky, but someone still has to decide to keep unpopular reference materials for them to remain available.