To the items mentioned by other contributors I would add what I consider the 800 lb gorilla in this room.. On some models with electric landing gear, the actuators have a recommended inspection / replacement of an internal spring. These should be replaced every 1000 hours to ensure they do not fail. This is not a mandatory replacement but the gotcha is if a spring breaks the gear will not function. That means the gear will not retract nor will it extend. The actuator will be frozen and the significant thing to note is that the alternate extension procedure will not extend the gear. You will have to land gear up.
So in prebuy consider the fact that the replacement springs are no longer available, remanufactured actuators are almost impossible to find and include the subject springs anyway, so your only option will be to replace the actuator with a PMA’d part from a current manufacturer (Eaton) to the tune of apx $20k ..
I’m sure there are many actuators out there beyond the 1000 hour interval working just fine and will for the life of the airframe but the bulletin exists and there is always the risk of the problem occurring rendering the gear inoperable.
