P2V+ V3.0 here. I fly 3 batteries almost daily except in rain, excessive humidity, and heavy wind. How long can I expect these 4 motors to hold up. Should I swap them out eventually?. So far they sound, look and fly okay but 400 feet up is a bad time to need to change parts. I saw a YT vid of some guy using a cheap tach meter to check each motor's rpm. Is this a good idea? I called DJI and the "federal work study students" answering the phones are seriously lacking knowledge of their products.