Depends on the show. Better Call Saul, The Americans, and Game Of Thrones were shows I binged watched until I caught up, but I had no issues remembering things. I have retwached all those shows again and my memory has held up. There wasn’t plots or characters I completely forgot about.

Ozark on the other hand….for the life of me I can’t recall what has happened in that show besides some vague overarching plots and some character beats. I did a rewatch in preparation for the last season and I couldn’t believe how many major characters or plots I just completely forgot about