Using just one credit all month long can have few positive outcomes. First and foremost, it can show you exactly how much your are spending overall, and on what. If you take the time to break down your expenses and write everything down you can set up a budget for yourself and perhaps make some changes regarding your spendings, if you feel that you spend too much on food, for example, or weekend entertainment. Be sure you can pay off the monthly bill if you plan on going that route.