Many people have been through this decision in the past few years. It’s pretty simple; if interest rates drop significantly below the rate of an existing mortgage, refinancing may make sense.
Advice from HUD (US Dept of Housing & Urban Development) experts is “2% and 18 months.” If you plan to remain in the home for at least a year and a half, and if you can qualify for a rate that’s 2% lower than your current rate, refinancing is worth a look.
Keep in mind that refinancing is not free. The refi process involves many of the same inquiries, validation and fees as the original financing. “Rolling the costs into the new loan” can mask the long-term financial impact. Compare the math carefully.