I close most of my tabs every 15 minutes or so. If I need to find a window I just closed, I look in my history. Browser history seems to be the best kept secret.
I do have a smart RSS reader YOShInOn which lets me favorite articles, I definitely do look at my last few days of favorites regularly when I am looking for articles to submit on HN and elsewhere but it’s true that I hardly ever look at older favorites. Still I’ve got the ambition of being always able to back up the outrageous-sounding things I remember reading about when I write comments online with citations.
Or those who stuff everything into a read-it-later app or so-called second brain tool in the hope that they'll get to all (or just some) of it "one day". That day rarely, if ever, comes.
I can't imagine not closing browser/dumping all cookies and state at least once per day.