There are six stages in the classical life of a product. These may be extended over time-scale, maybe few months for a fashion item or several years for a car or some other consumer durable:......you have the development of the product,......following the development, there is the launch, it is launched in the introduction stage,.....is the production gains acceptance and sells, this is the growth stage,.... the fourth stage of majority comes next.....sales peak. reaching the saturation point. Having reached a peak,.... decline sets in,....the product is replaced.