I try to limit my book buying already for a few years, by wanting to read a book at least three times before I buy it. (doesn't always work, but at least it keeps me from impulse buying every book that sounds vaguely interesting.) Also I reread and lent from the library. so I do not always read new books exclusively. And once I read a book I wonder if I see myself rereading it, if yes it can stay, if no it can find a new home by secondhand bookstore or free little library.