Pros Walk a House Differently: Experienced investors barely look at kitchen finishes. They scan floors for slope, ceilings for stain rings, baseboards for moisture line, and the electrical panel brand. Cheap-to-fix things scream while expensive things whisper. The Electrical Panel Brand: Federal Pacific Electric (Stab-Lok) and Zinsco panels have decades of failure history. Insurance carriers increasingly refuse coverage. Budget $2,500-5,000 for full panel swap and add it to your offer math. The Basement Smell: Faint mustiness means humidity. A real damp earthy scent means active water intrusion. Look for efflorescence on block walls, rust on metal supports, and the paint tide line on wood framing. Foundation Crack Patterns: Hairline vertical cracks are normal settling. Diagonal at corners means differential settlement — get an engineer. Horizontal across a wall means lateral pressure failure — major structural. Stair-step in block that's widening means active movement. Granules in the Gutters: Asphalt sand-like granules in the gutter mean the roof is shedding its protective coating. Combined with bald or curled shingles, that roof has 1-3 years left. New roof needed that you didn't budget for is the problem. The Marble Test: Set a marble on hardwood and watch. Slow drift is normal old-house settling. Picking up speed means joist sag, foundation movement, or termite damage. Then check the doors — if they don't close cleanly, two stories that match deserve an engineer. Galvanized Plumbing and HVAC Age: Galvanized supply lines last 50-70 years and need full repipe ($8K-20K). HVAC over 12 years is on borrowed time; over 18 should be priced as 'replace this year' ($8K-15K).