The most common reason to refinance is to lower your payments when
interest rates fall. The rule of thumb is you should refinance any time
your savings will pay back the closing costs over a period of time shorter
than how long you plan to own your home.
Another reason to refinance is to eliminate costly PMI. If you paid
less than 20% for a down payment, then lenders usually require PMI.
I've seen PMI as high as 0.6% of the loan amount so a $250,000 loan
would have you paying $1,500 a year just for insurance! When your house
appreciates so you have 20% equity, then you should refinance and eliminate
this PMI payment. It might even make sense to use any cash windfalls
to "buy down" your mortgage with a refinance to an 80% loan
and eliminate this very costly insurance that is unnecessary once you
have 80% equity in your home.
Many people refinance their homes to take money out to remodel or do
major home repairs. This often makes sense when you have many years
of appreciation and any money taken out would still have you with greater
than 20% home equity. I DO NOT recommend people take money out of their
homes to buy autos or other items that don't last as long as a home.
Some people discover they have had several raises since their first
mortgage and they can afford to pay more every month. If you are in
this lucky group, then you can refinance a 30 year loan to a 15 year
loan and get a better rate while saving thousands and thousands of dollars
on interest.