The context is “while tidying”. If you stop to peruse one of your 4000 books while trying to sort through them, that might be an afternoon or a week lost. Maybe well lost in a good book but a distraction if your goal is tidying. Entirely your choice, though. If you don’t know which books you love just by touching them, what does it take? Is this really that hard?
Long before KonMari, I went through this process because I had to move bookshelves and books to paint. The best part is by touching every book (in addition to cleaning it) is that I reminded myself of a whole bunch of books I wanted to delve into again. Or even read for the first time. (I was so glad to finally really the Autobiography of Ben Franklin a couple of decades after buying it.).
I’m a person who might have three editions of the same book (or different translations of the same book) which I keep to compare. But I know where every book I have lives and even what book it’s next to…because every single book is chosen with intention. I often check out a book from the library several times before deciding that I must have a copy for my own.
In contrast, before the Kindle, my partner accumulated books like magazines…because he needed something to read on long plane flights. Unlike our collectibles, these are definitely books that are just taking up valuable shelf space that could be filled with much more loved books. So these are fair game. As well as no-brainers.
As a person who has always spent money on books first (before clothes, jewelry, makeup…and just about anything else), I’m having trouble understanding why other people find this hard. If you love it, keep it. If you don’t, don’t. Make room for the things you love.