If you’re a little savvy about credit, you probably know that each of us is entitled to a free copy of our credit report, once a year, from each of the three main credit-reporting agencies. You can access these easily online at annualcreditreport.com — and if you’re willing to pay a few dollars, you can get your credit score, as well.

Everyone knows the value of having a good credit score — apply for mortgages or credit cards and get the lowest interest rate possible because you have a 721 FICO Score. There are also a lot of Americans, especially in today’s economic times, who know how difficult it is to even qualify for those same mortgages and credit cards with a 521 FICO Score.

A credit score is either a blessing or a curse cast down upon you from the digital cloud. A score of 740 qualifies you for the best interest rate on a conventional mortgage. A score under 640 means ugly interest, and a number under 620 makes it very hard to get a mortgage at all.

Credit reporting bureaus continually update credit reports as they receive information from lenders. Your credit score may change with these updates as lenders add new information to your credit report but also as old information drops off your report. How updates affect your credit score can depend on your overall credit history.

FHA has a two-tier credit score system for insuring loans. First-tier loans require a minimum down payment of 3.5 percent, while second-tier loans require at least 10 percent. The first tier includes those with FICO scores of 580 or above, while the second tier includes those between 500 and 579. FHA does not insure loans with anything below a 500 credit score.