The fleet manager who made me draw every fuel line from memory
Old Bob at the Des Moines yard made me sketch the entire air brake system on a napkin before he'd let me touch his truck, and I got three fittings wrong, so now I do that on every new rig before I open a wrench, anyone else do a mental walkthrough first?
Skip the napkin trick, I get why it works for you, but for me that mental walkthrough just burns time before I even see the problem. The real learning happens when my hands are on the fittings, feeling how they sit, not when I'm playing a memory game on a greasy counter. Old Bob sounds like he had a point about respect, but I'd rather trace a line twice with a flashlight than stare at a blank page and guess.