Many of our Lumen textbooks are what we call “fat courses,” jam-packed with a wide variety of material. We don’t expect most instructors to use ALL the content in a given course, but we want you to have as many options as possible to choose from.
We do advise not to delete content that you know you won’t use, however. Instead, mark it as “private” in the Organize page, which will hide it from student view. You can also move it to a new Part at the end of the book, made for housing the items you know you won’t need.
That way, you can return to it later to mine ideas or content, should the need arise.