[joemi]

I'm not the person you were asking but it's happened to me too, with physical books, not e-books. I don't know if I can explain how it happens. I'd say that me not knowing the exact content of my bookshelf is similar to me not knowing the exact content of my fridge and pantry. There have been a few times when grocery shopping where I can't remember if I have a less-frequently-used ingredient (like cream of mushroom soup) but I'd like to make something using that ingredient soon, so I buy the ingredient, and then when I get home I find that I did have a can in the back of the pantry that I bought a year ago and the expiration date hasn't arrived yet. Oh well.

If you can really remember every single one of your nearly a thousand ebooks that you've bought, that's both impressive and baffling to me.

[yial]

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.

[joemi]

Oh yeah I can definitely remember all the books I've read. The only ones I've ever bought twice were ones I hadn't yet read but had sitting on my shelf for a while with the intention of reading sometime.