The idea of a credit card has existed since the late 1800s, but they really became standard in the 1950s. If you are like one of 177 million Americans, you have at least one credit card. If you’re like most, you have somewhere between 3 and 5 cards. Fortunately, the number of credit cards you hold is not indicative of amount of debt you hold. Here’s a little guidance through the American credit card mire.