I have had opportunity from time to time to get a hold of aircraft life vests that have reached their expiration date and can no longer be used aboard the aircraft. This has provided me with the opportunity to try them out. I have also had some flight attendants deploy and inflate them. Even after their training in the airline safety program are startled and surprised when they go through the full process and pull the handles on a live vest and fire the inflation cylinders. In training they are taught how to put it on and how to demonstrate how to put it on for the passengers but most never actually have the chance to fire a live vest. Last week one of the flight attendants with 10 years experience fired a life vest for the first time. It startled her. In those few seconds she learned so much more about using the life vest that she did not know before. Always the people that have the opportunity to try one are very appreciative because they did not realize what would actually happen.