A certified dji repair facility can inspect a drone for it's overall condition and air worthiness. They can report on the drone in their invoice, example: "This UAVs serial #123456 has been inspected and found to be in good working condition and safe to fly by a qualified operator under normal conditions". I have a check made of all my drones every 6 months or when I sell one. It gives me reassurance that I have not missed something and piece of mind to the buyer. I'm not talking about a Cessna 210 going in for an annual or a high time item. And I believe the pilots on this forum to be intelligent enough to know the difference.