A tiny number of tabs... but soon it becomes out of control!
Here are two Chrome extensions I find super useful. By the end of the day I usually have 30-50 tabs open which can cause issues. I would highly recommend using them even if you don't collect tabs like I do.
The Great Suspender
Too many tabs can cause a drain on your system resources. This extension will suspend, put to sleep, any tab that is left idle over time. To awaken the tab just click in the middle of the page. You can add any page to the whitelist so it never gets suspended. I usually just add my calendar and email. I would assume teachers would also add SIS.
I just added this one recently. When I find myself with too many tabs I can just click one button and all the tabs will be put on one page in a simple list. I think this is a great way to save my thinking after a long period of researching a topic.