My friend Chris on his old Trek had his left crank arm just fall into the street while he was pedaling uphill. He coasted to a stop holding just the pedal. It turned out he had put the crank on himself a month before and forgot that final tighten after the first few rides. He had to walk the bike three miles home in cycling shoes. Now he checks that pre-load like it's a religion before every single ride.

My buddy's truck threw a check engine light last month. The scanner at the auto parts store said it was the catalytic converter, which is a huge bill. He was ready to sell the thing for scrap. Then his neighbor, an old timer, asked if he'd checked the gas cap. It was loose. Tightened it, light went off in two days. Saved him thousands because a sensor got confused by a simple vacuum leak.

Wow, I totally used to think sensor placement was just about the tech specs and building layout. Reading this and seeing @emery951's comment about their cat really shows how wrong I was. It's all about the actual living happening inside the house, not just the walls. That shift in thinking, from just installing to actually listening, makes a huge difference.