Mortgage rates have been hitting historic rates nearly every week for a while now. According to Freddie Mac, the average rate for a 30-year fixed loan was 4.32 percent last week, and the 15-year average hit 3.83 percent.

Are you thinking about refinancing your mortgage? Are you not sure how much money you'll save if you do - or if you'll even qualify for a new loan?

Here are six questions to ask yourself before you refinance.