Is it worth refinancing to save $100 a month?

You need to factor in your break even point when you decide to refinance. This is when your monthly savings offsets the cost of refinancing. So, if it cost $5,000 to refinance, and you’re saving $100 a month, you’ll hit your break even in 50 months. If you’re planning to sell the house before then, refinancing might not be worth it.