ECHO24

You replace a servo and record it in a log book. Hobby electronics have no quantifiable service life, i.e., the new servo has no defined service life or correlation with the life of the one replaced. Why bother recording it? General aviation parts go through rigorous testing and certification, and there is a huge database from decades of real-life use, definitive information maintenance schedules can be based on. Without that, RC log books are useless. If jets use some type of certified gear that might not be the case, but that includes all hobby electronics, not just RC planes. That's why it's cheap.