A common homebuying rule advises keeping mortgage payments at or below 25% of monthly take-home pay, using a 15-year fixed loan with 20% down. However, with current 15-year rates around 5.44%, this limits affordability to households earning about $140,000, excluding many buyers. Rising taxes and insurance further strain budgets. A 30-year loan lowers payments but is discouraged by this advice. The rule protects against being house-poor but may now be unrealistic in today's market.