Traditional development or sequential approach
Simultaneous engineering

Starting from the fact that the life of a product is similar to that of a human being, in that it passes from life to death, we will reason here from a chronological point of view. We distinguish between the product and the project dedicated to it, and begin by defining a product's life cycle, which should not be confused with its life curve. In fact, the life cycle represents the succession of product development, manufacturing, distribution, operation, maintenance and disposal phases (figure 1). This life cycle is part of the more general framework of a generic product's life curve, which represents all products manufactured according to this model. It is composed as follows