I know this isn't a unique or probably that interesting a question, but here it goes. I have only until tomorrow to decide (appraiser coming Monday am). I have $303,000 left on a $337,500 30 year mortgage. I'm about 2.5 years in and the rate is 4%. The refi would be to a 30 year at 3.62%. The closing cost estimate is $3600 (it's a condo in Brooklyn. I don't think I can find cheaper). Since month 1 I have prepaid $500 principal. I plan to continue to prepay $500 a month. I am in the 33% tax bracket. I max out my 401K and IRA (not tax deductible) each year and save at least $1K a month in my taxable account, usually more. I prepay my mortgage as I guess kind of a hedge so I'm not dumping all of my savings into the market. I have enough in cash/stocks to pay the whole thing off right now if I want to, but have no desire to do so. I do plan to continue to prepay the $500 a month. I was thinking it could be good to lower my monthly required payment because if I decide to career change which I would like to in a few years, then I can take a pay cut and still be able to pay from my earnings and not have to tap savings. I have played with a bunch of calculators and get a different estimate for savings for each which is why I'm unsure if this is worth it. Also, I plan to keep this condo. If I move someday, I will use it as a rental property.