I should have read more than 1000 books myself, but only a small part of the books in my bookcase. In order to cherish, the entity that keeps books is understandable. However, the entity that keeps books means that it believes that it can be read at any time. The result is that every time I read it, I don't want to go deep and leave the questions for later. Most books are actually not that valuable. Many books I have read are only worth tearing off a page or copying a sentence to save. So, after a while, I will clean the bookshelf once. Send those popular books, or well-read books, or sell them as waste paper. Only those books that are extremely valuable and worth reading repeatedly will be left behind, or absolute orphans and remnants can only be collected. Some books can be read for a lifetime. Fortunately, there are not many such books, and one's reading surface is not very wide. One or two bookshelves are enough.