Just because fixed rate mortgage rates have dropped to historic lows doesn't mean that you should automatically refinance. With the economic climate you might not be able to refinance because many banks have tightened the rules for refinancing. As for who is eligible, you will need a 700-720 on your credit score to get the best rates. To refinance at all you need at least a 600. Generally it is worthwhile to refinance if you can save at least a half point off of your current rate. But you do want to be sure that you will have enough time to recoup the cost associated with the refinance. If you move or sell the property too soon you will not be able to recoup the costs of refinancing. If you are in a variable rate mortgage this may be the time to switch to a fixed rate as long as you plan to be in the home long enough to justify the costs and allow you to see the savings.