i don't drink shakes ever so the answer is never, how many times do you see some skinny kid do his workout for an hour and then run to the bar and scream "protein! protein!" .. i can't believe people actually believe that they need a shake after a workout, but that is what 30 years of marketing by supp companies do
you don't need to take supps after a workout. what i recommend is eating good fats after a fasted workout.