And going back to the original question, 'what flying schools don't teach you...':
How to park multiple helis in a hangar that would initially seem to be too small to fit them all.
2 blades, 3 blades, 4 & 5. All with heads at different heights. It can seem like a jumbo game of Tetris at times...!
(And only something else that has to be picked up 'on the job').
Regards,
B73