'Don't know about tabs alone but I regularly have 20-30 windows open. Many of those have more than 3 tabs. Firefox starts to get a little slow beyond that count on my machine.
I usually finish before I get to the end of the tabs, then I get sad because I probably won’t ever revisit those tabs. Maybe they would have been “the one?” Forever lost.
Before it broke, I had 58 tabs open on my phone, currently I have only 19. Although on desktop I generally don't cross 10.
But my aunt surpassed everything.
Her Chrome (Android) doesn't even show a number anymore. It's just ":D" - https://i.imgur.com/R2QfIFQ.jpeg