MarketWatch's Jim Jelter describes the worst mistakes you can make financially in your 20s, 30s, and 40s, the decades of your life which are so critical to long-term financial security. (Photo: Getty Images)
The credit score is one of the most important parts of your finances. This three-digit number gauges how responsible you are with money and can determine what interest rates lenders will charge you on mortgages and auto loans. The most important part of maintaining a strong credit score is to pay your bills on time. Another major component of the credit score formula is how much debt you owe, or your utilization ratio, which is how much debt you owe vs. the total available credit limit you have.