With modern communications tools such as e-mail, online shopping and fax machines, it's easy to purchase supplies without ever coming face-to-face with vendors' sales representatives. No muss, no fuss. But before you close the door on an old-fashioned customer-supplier relationship with a sales rep, consider that these relationships can save you time and money in ways that are impossible when you purchase without dealing directly with the rep. Here are five benefits that only a strong personal relationship with a rep can bring you.