Estimate the full monthly cost, not just principal and interest
Include property taxes, homeowners insurance, HOA, and a maintenance reserve (many people start around 1% of home value per year, divided monthly). Example: $2,400 P&I + $520 taxes/insurance + $150 HOA + $400 maintenance reserve ≈ $3,470/month before utilities. Compare that to your stable take-home and other goals.
Check cash after closing, not only the down payment
Closing costs, moving, and immediate fixes can drain savings fast. A practical test: after down payment and closing, do you still have an emergency buffer (often several months of expenses) separate from the house? If the purchase zeros out your cash, small surprises become credit-card debt.
Stress-test income and lifestyle
Ask what happens if income dips 10% or a big expense hits in year one. If the only way the payment works is perfect months with no surprises, that is a signal to buy less house, wait, or increase the down payment.
Use a simple decision frame
Affordable usually means: payment fits with savings still happening, buffer intact after closing, and you can still fund retirement at a sustainable rate. If two of those fail, pause and revisit the price, location, or timeline.