5k tabs
At 1k tabs firefox was snappy and responsive, but at 5k tabs it was bad, very unstable, buggy and sluggish.
Firefox would crash often even doing simple tasks, some times it took 2 or 3 tries to open firefox. scrolling through all the tabs a couple of minutes.
But all good things must come to an end. Now I close any extra tabs, have 5 - 30 tabs open.
Something like that. At first I opened tabs for ”This sounds interesting I will read / watch it later” or ”I’ll probably need it later” This got me to ~300 - 800 tabs but then it became a joke, I just left tabs open knowing full well where not needed. Some times keeping all tabs open payed off like, using the search feature to find back to a project I left off. This happened very rarely.