Your credit score has become the single most important tool institutions use to determine your creditworthiness. They use this score to determine the likelihood that you will pay your bills on time.
When you want to borrow money from a financial institution or when you apply for a job, an apartment, or an insurance policy, your credit score will influence whether or not you get what you want. Having a good credit score also is an excellent money saving tool, as you will be able to get better interest rates. On mortgage loans alone, a ¼ % difference can mean thousands of dollars over the life of the loan.
To keep your credit score high, use your common sense: Pay all your bills on time (at least the minimum amount); pay your mortgage on time; don't open too many credit cards; don't max out your credit cards; and the longer you maintain your credit cards, the better.
If your credit score is low, don't despair; there are many things you can do immediately, as well as over the long term, to improve.
Read this blog post: Let's Do The Numbers - Secrets of the FICO Score Revealed