Decisions

How to think through a big money decision

Should you pay off your mortgage or invest? Lease or buy? There's rarely one universal right answer — but there is a better way to think about it.

Compare the guaranteed return to the uncertain one

Paying off a 22% APR credit card is a guaranteed 22% return. Investing in the market is an uncertain 7-10% return, on average, over the long run. As a rough rule, a guaranteed return above what the market has historically paid usually wins — which is why high-interest debt almost always comes before extra investing, and why a low-rate mortgage is a much closer call.

Separate the math from the feeling

Some decisions have a mathematically “optimal” answer that still isn't the right one for you. Paying off a 3% mortgage early usually loses to investing on paper — but if carrying that balance keeps you up at night, the peace of mind has real value too. It's fine to pay a small premium for sleeping better, as long as you're doing it on purpose.

Ask what happens if you're wrong

Some decisions are easy to reverse — you can always increase a 401(k) contribution next year. Others aren't — cashing out a retirement account early is hard to undo. Give the harder-to-reverse decisions more time and more certainty before you act, and treat the reversible ones as safe to just try.

The decisions people ask about most

Roth or Traditional usually comes down to whether you expect to pay a higher or lower tax rate later — see the full comparison. Lease vs. buy usually favors buying if you keep cars for years, leasing if you always want something newer. Refinancing is worth it once the new rate saves more over your expected time in the loan than the closing costs cost you upfront. None of these have one right answer for everyone — they have a right answer for your numbers.