Mortgage is a long term loan and the mortgage monthly payments form a major monthly expense. A lower mortgage rate means lower monthly mortgage payments. This is one reason why people hunt for low interest rates on a mortgage.
As we know, there are different types of mortgage rates and different people prefer different types of rate. The other thing to consider is that the market rate is constantly changing so at the time you entered a mortgage, the interest rates could be higher than the current rate. And this is where mortgage refinancing comes in.
When people talk about mortgage refinancing, they mean the full payment of the current mortgage loan by entering into a new mortgage loan at a lower rate. So mortgage refinancing starts making sense as soon as the difference in the interest rates becomes significant. A good example would be between 1.5 to 2 points in difference of interest rates. The decision to refinance your mortgage is also dependant on the remaining term of your mortgage. It wouldn't make sense to refinance anything if you've only got 4 or 5 years left on your current mortgage.
There are of course costs to mortgage refinancing. These includes prepayment costs for the current mortgage, closing costs of the new mortgage as well as other frees. Most of the time, people use mortgage refinancing as a tool to move from a higher adjustable rate mortgage to a lower fixed rate mortgage.
Another reason for mortgage refinancing is the need for money. So, if you have built a significant home equity, you can use mortgage refinancing to get a home mortgage loan that will generate cash for you. Debt consolidation is another big reason for mortgage refinancing. You can use mortgage refinance for creating money to get rid of high interest debts (like credit card debt, personal loans etc). This way you'll actually be able to save money, and more importantly your credit rating.
When done right, mortgage refinancing can help you save up a huge amount so it's something to consider. However it's not without risks so only exercise your right to refinance after you've properly evaluated your situation and needs.