<sermon>
My cards all have a 0% interest rate since I don't carry a balance. Since even the lowest are 9-10%, carrying a balance is a really bad idea compared to living within your means.
Carry just an average $1,000 balance and you're missing out on $100/year or more that you could either save or spend on something you want instead of giving it to the CC company.
Many people who carry a balance find that it creeps up and up until finally they're going even deeper in debt with consolidation loans or bankruptcy.
</sermon>