How to prevent failures on power transmission parts

Someone always complain frequent failures of power transmission parts. When questioned about their solutions, they would reply that they simply replace the failed parts with new ones. Same failures would re-occur if the root that cause the malfunctions had not been found. Generally, repeated malfunctions of power transmission parts are usually caused by work failures of other parts of the machine. One simple method to prevent some failures is to install each part of machine according to the specifications. And machines should be well maintained regularly; thus, some malfunctions can be detected ahead of time, such as transmission belt loosing, bent or broken gearings.