The roadside bhaiya selling sunglasses and umbrellas around my street lives by this lesson fully. On surface, he sells seemingly unrelated products but a closer look at his business sense makes me wonder. He knows that when it’s raining, it is easier to sell umbrellas and on a sunny day, customers demand sunglasses. With both items to sell, his product line is varied enough to reduce the risk of losing money during any season. Smart, isn’t it?