I never really need more than one YouTube tab. I can’t watch more than one video at once, and if I want to watch something later, I use YouTube’s own “watch later”. But in my 300+ tabs there’s likely several copies of my subscription box. Because rather than scroll through the tabs I can just press ctrl+t and type YouTube in. This not only happens with YouTube, but with every bookmarked page I have, from the HN front page to the site I use to check the weather.