My instructor told me to always trust the manual over a hunch
I was troubleshooting a faulty transponder on a Cessna 172 and thought I had the bad LRU pinned down. He said to check the wiring diagrams in the AMM first, and sure enough, it was a corroded pin in a connector I'd skipped. Anyone else have a story where the book saved you from a rabbit hole?
My old history teacher used to say footnotes were the first hyperlinks. I'd spend an hour chasing one reference to another book. That's how you end up with a stack on your floor you never planned to read.