Project Life Cycle

A project life cycle represents the sequential grouping of the project phases, from the beginning to the end of the project (Figure 2.1). The time between the start and completion of a project represents the project life span. In project life cycle, the project starts with a gradual build-up in the use of resources. It is followed by a long-duration plateau and towards the end, there is a rapid run-down as the project draws to a conclusion. Although construction projects differ in many ways, but most of these follow a similar life cycle pattern.

  Typical Project Life Cycle (Not to Scale)

There is a difference between the project life cycle and the project-product life cycle (commonly referred as product life cycle). A product life cycle includes the period from the start of the development of the project, it is followed by the construction of the production facilities. The product production starts after the construction phase and it lasts upto the time when the product reaches its "kill point" due to any reason such as obsolescence, lapse in demand or failure to produce it economically. The'product life cycle is made up of its project life cycle plus its useful operation period. The product life cycle, from the point of view of project promoter or investor, can be categorized into three phases, i.e. pre-investment phase, investment phase and the product operation phase. 

Note 

The probability of successfully completing the project is lowest at the start of the project, and hence, the risk and uncertainty are highest. The probability  of completion generally gets progressively higher and the risks reduce as the project continues. 

The ability of  the stakeholders to influence the final product (facility/service) and the final cost of the project is highest at the start and gets progressively lower as the project continues.