Start with what the ARM actually buys you, which is usually less than people expect: often only about a quarter percent off the 30-year fixed. For that small a discount, most borrowers would rather keep the certainty of a fixed payment. A true one-year adjustable is also rare now. What gets called an ARM today almost always has a fixed period of five or seven years before it can move at all, so the adjustable part may never touch you if you sell first. The case for the ARM strengthens only if two things line up: you're genuinely confident you'll be out of the loan within a year or two, and you expect to refinance into something meaningfully lower before any adjustment. Borrowers have ridden adjustables down in past easing cycles and come out fine. But that's a bet, and nobody can promise where rates go or when. A gentle push on the premise, too. A plan built on selling before the market drops is a market-timing call, and nobody times that reliably either. The stronger plan keys off your own timeline, the actual spread you're quoted, and a worst case you can live with. If the fixed-period ARM saves little and your exit date isn't certain, the 30-year fixed is usually the calmer choice. Either way, the call is yours to make with the real numbers in front of you.