Products, like human beings, have a limited life. They are created to fulfill a need. When a firm is able to fulfill a need better than its rivals, it gains mo­mentum and speed. Such products grow quickly. Both profits and market share would improve quickly, and begin to mature after a while when rivals begin to hit back.
Finally, products see the end of the road, when customers get disenchanted. They stop buying the product and the product ceases to exist. A new product, thus, progresses through a sequence of stages from introduc­tion to growth, maturity and decline. This sequence is known as product life cycle (PLC).
To say that a product has a life cycle—according to Philip Kotler is to assert three things:
Products have a limited life,
Product sales pass through distinct stages, each posing different chal­lenges, opportunities, and problems to the seller,
Products require different marketing, financing, manufacturing, pur­chasing, and human resource strategies in each life cycle stage