A customer in Flagstaff showed me a trick with a mirror and a phone flashlight
I was doing a standard inspection on a stone fireplace up there last fall. The homeowner, an older guy who used to be a mason, held up a small hand mirror at the bottom of the firebox while I shined my phone light down the flue. He said, 'You get a better angle on the smoke shelf this way, see?' It let me spot a big chunk of fallen tile I would have missed with just the headlamp. I've used that combo on every tricky, shallow fireplace since. Anyone else have a simple tool hack like that for inspections?