Used to think that way too, honestly. Figured if nothing was rattling or leaking, it was good to go. Then I saw a landing gear collapse on a plane that "wasn't broken" until it very much was. Your find on that actuator proves the book exists for a reason. It's not about fixing what's broken, it's about knowing what could break next. That senior guy's rule only works until the day it doesn't, and then you're explaining why you skipped steps.

But how often do boilers actually blow up these days? Modern ones have a lot of safety valves and shut-offs built in. Maybe skipping one test isn't the huge risk people make it out to be.

Sharpness matters more than the steel's age.