Interesting comments. As for the wire tester - you’re talking about the inductive types with a clamp that goes around the insulated wire? I’m not sure how common those are. I’ve got about three of the regular multimeters with the + and (-) probes. One of them even has batteries that still work!
With regard to the iron - we have plenty of it in our blood. Some folks may have a better make up that gives them a better sense of direction. I’ve heard where folks that sleep with their head to the north do better with directions as well.
I was just telling my kids that there is still SO much to understand in this world. Makes it fun!