Since you're not dorming, it won't be near as much use, but at RPI you're pretty much SOL without your card. Most buildings after about 8-9ish you need one to get in, cafeteria and various cafes, you can use it to buy a lot of things tax free on campus, if you're loitering at night and security comes up you better damn well have it, charge things to your bursar account (aka, make your parents pay for books), certain computer labs, certain rooms, library, rec center.