Just remember that anecdote != data and all that.
My ff gets restarted in two cases - ff or kernel gets security patch. That sometimes means a month of no restarts. (With maybe 30+ tabs in different groups open)
FF on Windows (work) is rock solid for me, while on Mac (home) it becomes unusable (too slow) after a few days, and also is a memory hog. I do keep 100s of tabs open on both, although most of those are usually not loaded.
