Why You Need a Filter: You can't build a detailed pro forma for every property. Quick filters eliminate properties that have no chance of working. The Quick-Filter Toolkit: 1% Rule (rent ≥ 1% of price), 50% Rule (half of rent goes to expenses), 70% Rule for flips (≤70% of ARV minus repairs), 2% Rule (unusually strong if rent exceeds 2%). When Rules of Thumb Fail: Expensive coastal cities rarely pass the 1% test but still cash flow. Cheap rural markets always pass but have high vacancy. Building Your Personal Filter Stack: Layer filters: price range, neighborhoods, property types, bed/bath counts. Goal is to eliminate 90% of listings quickly.