MY 2 cents worth. I have found that when I was instructing the full use of checklists dropped dramatically as soon folks got their PPL and started flying on their own. Personnally I think the problem was trhe checklist were not very good. They were too long ( the C150 checklist had more items than the checklist for the DC6 firebomber I used to fly
). Also the checklist did not flow very well . As the junior instructor on staff I failed to effect change but later I was responsible for creating checklists for several multi engine Cessna's and Piper models flown single pilot IFR. My philosophy was as follows.
1. Each block was assigned as a "do list " or a "checklist"
A do list means you read the checklist and do the item. A checklist means you do all items from memory and then check them.
Therefore you get
Prestart=Do
Afterstart=check
First flight=Do
Pretakeoff=Do
Line up=Check
Climb=check
Cruise=Do
Approach=Do
Landing=Check
Afterlanding=check
Shutdown=Do
All blocks follow the same flow. Starting at the floor between the seats the checks flow up the centre consol, around the panel from right to left and finish on the left ( or overhead ) switch panel. I have had quite a bit of positive feed back from other pilots with this system.