What performance benefits can players expect from installing a shaft that is longer than the standard 45 inches?

The most obvious result would be an increase in clubhead speed. What I have found is players get a better sense of feel for the clubhead position. But remember, a longer shafted club demands more respect, and when the player respects a long club, the rewards are big. Respect means they do not have to swing out of their shoes to hit the ball a long way. With longer shafts, even a smoother tempo will launch the ball higher and carry further.