Picking the wrong credit card
If you earn cash back for traveling, you'd better not be a homebody. Or, if you use your credit card in all types of stores, don't sign up for a credit card that gives extra earnings for specific purchases only.
In both cases, you're not getting the most from your spending. There might be a card that better fits your habits.
"Understand how you spend, and then select a rewards card," says Bill McCracken, CEO of Synergistics Research, a financial services market research firm in Atlanta.
Some cards offer the same rewards potential for every purchase, while others offer accelerated earnings for certain categories.
The most common accelerated cash-back category is gas, followed by supermarkets/groceries and dining/restaurants, according to Bankrate's 2013 Credit Card Cash-Back Rewards Survey. But there are other, less common categories that may be better suited for your spending habits, such as utilities, parking and drugstores.