There are three considerations when inspecting props. There are the blades, there are the hubs that they attach to, and there are the motor brackets that the prop hubs attach to on each motor. When I check my blades, I give them a bit of a twist to check for cracks, and this also allows inspection of where the blade is riveted to the prop hub. Its a cylindrical shaped flange, and by twisting the blade, you can check to make sure there are no cracks around the rivet. Inspecting the prop hub is a matter of assuring all of the flanges are intact, and inspecting the motor brackets involves making sure they are snug to the motor and not loose, as well as assuring the spring is intact. Lastly, when each prop is installed, you should be feeling very little play if any when you gently rotate the hubs CW and CCW on their brackets. If an otherwise serviceable prop begins to develop play, replace it, and if the play remains, it may mean that the motor bracket needs to be replaced. Just remember during inspection and maintenance, that the props are a system of multiple parts.
