We played a game at our airline where you had to plan your weight and wind in a 737 so when you went to idle power at FL350 you couldn't touch power until 1,000 ft to stabilize or use speed brakes or you lost, all you could do was vary the speed a bit to stay on profile. It wasn't that hard and saved fuel plus made you a better pilot by keeping you in tune with how to efficiently use your piloting skills to get the most out of your aircraft. I even did it with the 757 because knowing how we would be maneuvering for landing I could do it better than the VNAV.