Choosing between mortgage options rarely comes down to a single obvious "winner" — it's a genuine trade-off between monthly affordability, total lifetime cost, and how long you actually expect to stay in the home or keep the loan. Comparing options side by side with real numbers, rather than relying on rules of thumb, almost always reveals a clearer picture than gut instinct alone.

A common ARM structure is "5/1," meaning the rate is fixed for the first 5 years, then adjusts annually based on a reference index plus a margin. If you're confident you'll move or refinance within that initial fixed period, an ARM's lower starting rate can meaningfully reduce your costs during the years you actually hold the loan — but it introduces real uncertainty if your plans change.

Worked example: on a $300,000 loan, paying 1 point ($3,000 upfront) might reduce your rate from 7.0% to 6.75%, saving roughly $50/month. Break-even = $3,000 / $50 = 60 months (5 years). If you plan to keep the loan longer than 5 years, paying the point saves money overall; if you expect to sell or refinance sooner, you'd lose money on the upfront cost.

It's easy to focus only on the monthly payment when shopping for a mortgage, but the total cost over the full loan term often tells a more important story. On a $300,000 loan at 7% over 30 years, total payments equal roughly $718,800 — meaning $418,800 of that, well over the original loan amount, is interest alone. This is precisely why comparing total interest cost across different term lengths and rates — not just the monthly payment — is essential before committing to a 30-year obligation.

A larger down payment doesn't just reduce your loan amount — it often unlocks better interest rates (lenders view lower loan-to-value ratios as less risky), eliminates PMI entirely once you cross the 20% threshold, and reduces your total interest cost on three fronts simultaneously.