The working world isn’t the same as it used to be. With millennials changing jobs four times in their first decade out of college, according to a recent study by LinkedIn, we’re a long way away from the time where people stayed at the same company from first day to last.

On the way to a successful career, decisions have to be made, some of which will prove critical. One good decision can have positive repercussions for years, but so can one bad decision. Where decision-making is studied - mostly at business schools and departments of government - there's a kind of...