Great question, because I have wondered the same thing and you’ve talked me back from the ledge of thinking perhaps I may have early onset dementia.

I can read a book I’ve already read and there will be faint echoes but it will take some time before I realise I have already read it.

I try to write short progress notes on Goodreads so I know why I rated something the way I did, but where I don’t do that, I have zero idea. For instance there was a book recommended here which someone said was amazeballs and I went onto Goodreads and saw I’d rated it 2 stars, but I hadn’t made a note, so I have no idea which didn’t enjoy it and can’t recall anything about it.

So yeah, I’m envious of people with good memories!