Product life cycle refers to the whole process of products from entering the market to upgrading and exiting the market. Product life cycle is directly related to the formulation of product strategy and marketing strategy by enterprises, which is mainly determined by the changes of consumers' consumption patterns, consumption levels, consumption structure and consumption psychology. The product life cycle defined by marketing is: introduction period, growth period, maturity period and decline period.

A typical product life cycle can generally be divided into four stages, namely, entry stage, growth stage, saturation stage and decline stage.

1, entry period. When new products are put into the market, they enter the investment period. At this time, customers still don't know about the products, and only a few customers who pursue novelty may buy them, and the sales volume is very low. In order to expand the market, a lot of publicity expenses are needed to promote products. At present, due to technical reasons, products cannot be mass-produced, so the cost is high and the sales growth is slow. Enterprises may not get profits, but they may lose money. Products also need to be further improved.

2. Growth period. At this time, customers are already familiar with the products, a large number of new customers start to buy, and the market is gradually expanding. Products are produced in large quantities, production costs are relatively reduced, enterprise sales are rising rapidly, and profits are also growing rapidly. When competitors see that it is profitable, they will enter the market one after another to participate in the competition, thus increasing the supply of similar products, reducing prices, and gradually slowing down the growth rate of corporate profits, and finally reaching the highest point of life cycle profits.

3. Saturation period. The market demand tends to be saturated, there are few potential customers, and the sales growth is slow until it turns around, indicating that the product has entered a mature stage. At this stage, the competition is gradually intensified, the selling price of products is reduced, the promotion expenses are increased, and the profits of enterprises are reduced.

4. recession. With the development of science and technology, the appearance of new products or new substitutes will change customers' consumption habits and turn to other products, so that the sales and profits of the original products will drop rapidly. Therefore, the product has entered a period of decline.