I'm sort of OCD about open tabs. I close them whenever I'm finished (or think I'm finished). Worst case scenario, I open the browser history and navigate back to what I wanted. This doesn't happen very often. If something needs saving, it goes into my bookmarks.

Slightly unrelated, but I'm the same way on my desktop too. I hate open windows that I'm not actively using. I always force close things on my MacBook.

Edit: To answer the question, 1.