A mortgage is the largest loan most households take. Small rate differences compound into large lifetime differences over 30 years. Test scenarios below.
A common rule is total housing cost (mortgage, taxes, insurance) under 28% of gross income and total debt under 36%. Personal comfort should stay well under those ceilings to leave room for saving and investing.
20% down avoids private mortgage insurance (PMI) and shrinks total interest. Not required — many loans start at 3–5% down — but 20% is usually the most efficient option.
Fixed for stability and long stays. Adjustable if you plan to move or refinance within the fixed period, or if rates are unusually high and expected to fall.