Maintenance of aircraft
Every part and component on an aircraft is given a time life by the FAA. First the FAA determines how long a part or component will last, and for commercial air charter operators, these times are usually cut in half. When the FAA’s time limits are reached, the part or component must be replaced. Even though they still have half of their service life left. There are no exceptions.
Time limits are in actual hours of usage or calendar life. An example of calendar life for propellers is: Most propellers have a five year calendar life as well as an hourly limit. If a charter operator has a brand new aircraft which is not flown and it sits without being used, the propeller must be overhauled at the five year limit, even if it was never used.
On the other hand, private aircraft only need to replace a part or component when they fail. This is something to think about the next time your friend wants to fly you in his private jet.