I've had a little over a hundred open at one point... I go browsing on HN and reddit a lot. I click on a bunch of different links to open in new tabs, and once the tabs start overflowing, I move them to different tab groups, and eventually and forget about them. Since I usually close my browser when I am done browsing and reopen it when I want to browse again, it does not make much of a difference in terms of snappiness.