I very rarely have more than ten open and I would be curious to hear what the benefits of having so many can be. The only one I can imagine is that if you have a very slow connection, it may save you some load times.
In Firefox, I can access pretty much any website from my history or bookmarks by typing a few letters of its URL or title in the address bar.
Usually when browsing a site that has multiple interesting links, which I open in a new tab whilst I finish reading the main site.
Then hit one of the new tabs, and well, GOTO 10. Doesn't take too many loops to open that many tabs. Then the task is to reverse the process, closing tabs as I read them.
In Firefox, I can access pretty much any website from my history or bookmarks by typing a few letters of its URL or title in the address bar.