Robarts is such a good library that I used to steal my friends' student cards to get access so that I actually had books to use for essays. If you go to Ryerson, you should do the same -- their library BLOWS.
But even if you can't borrow a card, you only need the student card to access certain parts of Robarts -- the rest are open to the public, but you blend in more if you're wearing the university student uniform of sweatpants and that permanently tired look on your face. During exam periods its open late late (sometimes 24 hours I think?) and it's so nice and quiet here that you can also take small nap breaks between studying if necessary. Once again, it is so unlike the Ryerson library, where there's a party on every floor, even the quiet ones.
Not only is it better atmosphere-wise, but Robarts has a huge selection of resources on all topics from all periods in history. Definitely worth checking out, even if you just need somewhere quiet to read.