What does it take for an idea to morph into the must-have item of the moment? How long does the hype last? Researchers have long referred to a five-stage product life cycle, but fads often accelerate stages and bypass others altogether. Remember that plastic circle we used to rock around our hips? Yes, I’m talking about the Hula-Hoop. The graphs below compare the life cycle of that once-beloved fad to your average product.