Your drone's rotors / propellers are built to be robust and flexible to avoid hurting people or damaging other items. Thus, bending will appear after various bumps. Check to make sure the propellers are properly installed before a flight.
Without a GPS signal, the risk of accidents increases
If you fly your UAV indoors, you will lack the GPS signal. For this reason, it is recommended that you always fly in open areas, as far away from tall buildings as possible. Incorrectly set compasses and return-to-home points are one of the biggest causes of drone crashes. Drone compasses can be intercepted by any magnetic and radio frequency (RF) source. Avoid flying in an environment with high electromagnetic interference, close to high-voltage power lines and mobile phone towers, as well as being too close to magnets such as car speakers during the transfer of unmanned aerial vehicles.
Check ports before flight
Always make sure your cables are well connected and carefully unplugged before flying to keep the ports in good condition.