There is no rule-of-thumb when it comes to refinancing because there are different reasons to refinance. If you are currently in an adjustable rate looking to get into a fixed rate loan, your rate and payment may change, but you will be in a better long-term situation knowing your rate and payment will not change. If your goal is to consolidate high interest debt, your loan amount and monthly mortgage payment may go up but your overall monthly cashflow will improve because you will have eliminated some or all of your other monthly obligations. There are also no-cost and low-cost refinance options that can lower your rate and payment with no or minimal investment. It is a good idea to go over your specific situation with a licensed loan officers to determine whether refinancing makes sense or not.