The number of sales and the length of a product life cycle might be different for different products but they all share a general pattern of growth and decline. This cycle can be shown on a graph ...

There is, furthermore, a persistent feeling that the life cycle concept adds luster and believability to the insistent claim in certain circles that marketing is close to being some sort of science.

Many businesses record and track sales information like this to help them know when to adjust costs and price, to boost sales and to extend the life of the product.