QDM and Whirly,
Yes, of course some take more time than others and some have the potential to do great things in a flying machine while otherrs will never get above just adequate but, it's not right to make blanket statememnts that, at a certain point people should be advised to give up.
Of course some students should be advised by their instructors that they may have limited potential but, how they proceede from that point is their decision, some enjoy being a perpetual student. Of course a good CFI will keep an eye on the progress of his students and switch them to different instructors if he thinks it's for the best.
I think we are having a heated agreement here; no two students (or instructors) are the same and the skill of an instructor or CFI is to make sure that the combinaiton is producing the best possible progress for the student.
Whirly, I hovered an R44 last week; not easy, hats off to you rotary types!
(PS, don't tell my fixed wing buddies I said that!)
3 Point