Our first time to participate but we have been reading posts since finding MMM while looking for advice on financial freedom. So here is our question we'd like to get input on. My wife and I are 36 and 40 years old respectively. We have zero personal debt outside of our mortgage. Balance is $407,000 at 3.5% fixed for 30 years (currently 1.5 years into the 30 year mortgage). Current value if home is $580,000. We have excess cash flow after both contributing the max to both of our 401ks and additional savings outside our 401ks. It would be nice to truly have zero debt by making extra principal payments to the mortgage. But, would it be wiser to save more (likely mutual funds) or start paying down our mortgage? Thoughts?