This activity is important because products, like people, have a life cycle. The product life cycle describes the stages a new product goes through in the marketplace: introduction, growth, maturity, and decline. The introduction stage of the product life cycle occurs when a product is introduced to its intended target market. The growth stage of the product life cycle is characterized by rapid increases in sales. The maturity stage is characterized by a slowing of total industry sales or product class revenue. The decline stage occurs when sales drop.