You see this piece of plastic everywhere. From the gas station to the bookstore, the supermarket to the mall. You know what it is and can readily identify it if quizzed. Have you figured it out yet? It’s a credit card, one of the most important financial tools in your wallet—a tool many students don’t know how to utilize. We talked with Tom Gannon, vice president of public policy at MasterCard Worldwide, to gain insight on how college-aged kids should (or shouldn’t) be using credit cards.