That’s it. That’s also why DronesBench comes with a novel, single efficiency benchmark for the electro-mechanical compliance of the drone as a system http://www.dronesbench.it/en/fomdrone/ . Just measure it at factory and write it on the plate or stick it somewhere on the frame, then measure again periodically during its operational life: significant decreases express hidden defects, thus becoming a preventive tool for flight safety.

Kit planes are the same way, but they still need to be certified before they can fly.