If my rate is 6.7%, is it better to buy it down to 5.9%, or put that money toward the down payment instead?

Our lean is against paying points, and in this matchup the bigger down payment usually wins the math anyway. Start with what the buydown costs. As a rule of thumb, each quarter-point of rate improvement runs about one discount point (1% of the loan amount), and it gets more expensive the further you push below the market's par rate. Going from 6.7% to 5.9% is nearly a full point of rate, which can run several points of the loan amount. Now compare where the same money does more. Using a round example, $122,000 spent on discount points saves a certain amount each month, but that same $122,000 put toward the down payment (borrowing less in the first place) usually saves more on the monthly payment. And points are a sunk cost the moment you refinance: if rates improve and you replace the loan, the buydown money is gone, while a bigger down payment permanently reduced your balance. Where points can earn their keep is qualifying and affordability: if you need a lower payment to fit the debt-to-income box or a hard budget, buying the rate down can be what gets the loan done. That should be your informed choice for that specific reason, never a lender's default pitch. The buydown-versus-down-payment side-by-side is something some people want to see, and we'll run that comparison for you on your real numbers in a Roadmap conversation.