The only criterion I have is that the books must look clean, which means that I have to disregard a lot of potential reading material in the charity shop. I don't use the library for the same reason, althought obviously, in principle and reality, libraries are life-enhancing palaces of wonder.
The speaker expresses their preference for books that are visually clean and well-maintained. This standard leads them to overlook many potential reading options available at charity shops. Their desire for aesthetically pleasing materials influences their book selection criteria significantly.
Despite acknowledging the invaluable role of libraries as enriching resources, the speaker opts not to use them due to similar concerns regarding the condition of the books. They recognize the importance of libraries in society but prioritize their personal reading experience, which is tied closely to the physical appearance of the books they choose to read.