Not the person you’re replying to but backing up what you’re saying - I read a lot of fiction for pleasure, I can say with some assurance whether I’ve read a certain fiction book, or, any book I’ve read for pure pleasure. (Though as time goes on and I get older… I once started reading a book and about 15 pages in realized I had read it before )

As a hobby, I do a lot of wood working. Recently I was acquiring some books on wood finishes. I accidentally bought one book three times - not all at once but over a several year period. I realized this while trying to organize.

Mainly because they can have very similar / generic titles, and be by different authors. Since I’m using them as a reference, even if I know the author, I can’t always remember if I own this book by them or maybe I own this book with very similar title by a different author.