The product life cycle describes the stages a new product goes through in the marketplace: introduction, growth, maturity, and decline. Product sales growth and profitability differ at each stage, and marketing managers have marketing objectives and marketing mix strategies unique to each stage based on consumer behavior and competitive factors. In the introductory stage, the need is to establish primary demand, whereas the growth stage requires selective demand strategies. In the maturity stage, the need is to maintain market share; the decline stage necessitates a deletion or harvesting strategy. Some important aspects of product life cycles are

(a) their length,

(b) the shape of the sales curves, and

(c) the rate at which consumers adopt products.