My T sometimes took notes, especially when she was younger, just starting out as a therapist. It's conversation, in the moment, and when you are "there" and trust the process it is not hard to remember stuff I don't think, anymore than it is for us with friends? I don't think the details particularly matter; I know after 6-7 years my T accidentally referred to my husband by a totally wrong name but those things are surface and not what therapy is about. You can't take notes for "connection"/relationships?