Would love to see a demonstration of energy management by many on these forums, especially those automation lovers. Nearing your destination at cruise altitude, autopilot and autothrottles off and maintain a smooth idle descent profile without Vnav or FD guidance, unnoticeable to the passengers and only adding power to vref N1/EPR at the outer marker with flaps in landing configuration.
I fully realize the limitations on practicing an art like this and the lunacy of attempting it on the backside of the clock after a 9 hour flight entering a hold at Ockham or JFK, but if your operation/airport permits it safely, manual flying is a neccessary part of a competent crewmember.