Every three or four years I pick a new subject. It may be Japanese art; it may be economics. Three years of study are by no means enough to master a subject but they are enough to understand it. SO for more than 60 years I have kept studying one subject at a time.
Peter DruckerNever ask who's right. Start out by asking what is right. And you find that out by listening to dissenting, disagreeing opinions.
Peter Drucker