A successful project management process relies on two activities: proper planning first, and then project execution. These two sequential activities form the basis of every project life cycle and can be expanded to suit the control requirements of every type of project in every area of project management application. The project life cycle, characterized by a series of "milestones," determines when the project starts, the "control gates" through which it must pass, and when the project is finished. The phased life cycle approach gives businesses more time to understand and assess future requirements and to make changes during the actual implementation phase. In addition, a phased approach gives the client quick wins, even at the very first phase.
The life cycle phases are important reference points for the project manager. They identify the system development life cycle in sequential time periods that sometimes overlap one another. However, the activities characteristic of one phase may be performed in other phases. For example, although most of the staff effort in analyzing requirements occurs during the requirements analysis phase, some of that activity continues at lower levels in later phases.