I do not know much about countries other than U.S., but I do know the logs must be very detailed. I've known two Navy Aviation Mechanics (Mechs) and the maintenance is so vital. As you mentioned in your post, the plane must endure fatigue stress and then after X amount of flight hours more testing is done. One man told me they would get down with a magnifying glass to find stress cracks.
Recently, I heard an advertisement stating that airline mechanics must get their hearing checked frequently. Why? So they can determine any difference in engine and other sound factors. Great post.
If because through the sound of the engine, can cause hearing difficulties and may be deaf so recommends earplugs as protection, thanks for dedicating read my post