Revolving Credit Lines

I am often shocked that people don’t consider that having a lot of credit lines open can negatively affect your credit score.

10 - 15% of your credit score comes from the types of credit used. If you have a lot of sources of revolving credit (i.e., credit cards), you can be seen as a credit risk because you have a greater potential of charging up the debt quick.
Let me give you a credit tip. Don’t even think about opening up store credit cards just to get a discount, and if you have any recent store cards, cancel them immediately and get them paid off.