The document discusses the four stages of a product's life cycle: introduction, growth, maturity, and decline. During introduction, companies focus on increasing awareness and promotion to get customer attention. In the growth stage, sales increase as customers become aware and companies focus on satisfaction. During maturity, sales level off and competition increases as companies spend more on advertising and managing distribution channels and competitors. Finally, in decline, sales decline and companies must decide whether to change, discount, or discontinue the product.