A project life cycle is a collection of phases in the project. Phases are subdivision of the project. Projects often have milestones and deliverables within the project which occur in phases. Life cycles can be documented with a methodology.

Regardless of the specific nature of work involved in the project, a project life cycle can provide a basic framework for managing the project. For example, regardless of the nature, size or complexity of a project, it can have the following generic phases:

1. start the project
2. organize and prepare
3. do the project work
4. close the project

As the project continues through phases:

1. stakeholder risk and uncertainty decreases
2. cost of changes increases
3. cost of doing the work increases (except for the closing phase)

It is therefore prudent to change requirements in the initial stages of the project.

Project life cycle vs product life cycle
A product life cycle usually contains sequential and non-overlapping phases. Phases are determined by manufacturing and control needs of the organization. Project life cycles occur in one or more phases of a product life cycle. A project may require many projects. For its new software, a software company would require feasibility study, market research, advertising campaign, or a new data center. All of these are projects within that products life cycle.

Project governance across the life cycle
Governance involves defining expectations, giving power to fulfill the expectations, and verifying progress. Project governance provides consistent and comprehensive methods to control a project to ensure its success. Project governance is described in the project plan and it must fit within the larger context of the organization. Phase structure provides a basis to control the project. Phases have to be initiated, monitored, and reviewed. Completion of one phase does not imply the beginning of another. Each phase is reviewed and evaluated by management before the next phase is initiated. A phase end it the best time to change expectation, reprioritize, and even decide to end the project.