Trivia: Last NHL Game Played With Only One Puck
I'm not sure when the NHL started doing that, but they certainly were not practicing that rule on November 10th, 1979. That date featured a game between the Los Angeles Kings and Minnesota North Stars. The entire 60 minute game was played with the same puck - not once was it deflected out of play or replaced.
The Hockey Hall of Fame was this rare puck displayed in the Hockey Hall of Fame, claiming that it was the last NHL game to be played using only one puck.