I keep an old beater trainer to put new RX's and new TX's in for at least an hour of flying before they go into anything new. I bench test new servos for the same hour as well. Doing this for over 30 years I have never had a servo fail to date in a plane. I have had two servo ever fail on the bench and they were in the past year both Jr servos one a 241 and the other a car steering servo forget the number and only one RX fail later and that was at least 15 years ago;It was a first gen Futaba FM forget the model number. Remeber nothing is perfect though.