I'm just saying that most of our new folks don't know how to plan their own descent. They have never been taught how. They only know VNAV which works OK most of the time, but if the VNAV is not behaving then they don't know what to do. How many times have you seen a guy pull the boards because he is 10 knots fast and the box says "drag required"? Never mind that he/she is 50 miles from the fix and could easily fix it without vibrating the pax and F/A's. How many times have you seen a guy NOT put in any winds, then lets VNAV start down with a huge headwind way to soon? 5 minutes later the jet is way slow and up comes the power.
I use VNAV about 50% of the time too, but I'm always backing it up with a little math in my head to make sure that it will be efficient. The new hires of today have not been properly taught how to manage their energy and plan an old school descent. I consider this to be a school house failure and I don't see it getting any better in the next 10 to 20 years.