I have multiple browsers and have different things on them. On my pc I use waterfox for youtube- and have no idea how many tabs I have open of videos I saw that were interesting, but I was busy so I opened them in background while I was watching another video. That, of course accumulates. Especially when I start music binging (I have two windows of waterfox dedicated to music alone). I then have vivaldi for everything else- with emails, reading stuff, and then official crap.
On my phone I've got three browsers- one I use for scribblehub, comics, and youtube with 49 tabs atm, another for RR and novelupdates with 45, and then a third for 'research' that currently does not display said tabs number. Same shit with youtube, I see something interesting while reading I open a tab in the background and keep it there. Especially if I've got multiple stories I haven't finished or caught up with ongoing at once.
I tend to only bookmark things that I wish to return to after finishing them, rather than what 'bookmark' implies, funnily enough...