Most businesses that are doing well now will, at some future point, do poorly. Things change—it is only a matter of time. Buggy whips were at one time a great business in America, video players were once the rage, selling and fixing typewriters a necessary and intricate part of the commercial equation. Now they are just things of the past with no economic promise whatsoever. Things do end, which is why you not only have to keep your eye on the ball, but also on the road ahead.

