How is a milestone used in project management?

Project management milestones are specific points within a project‘s life cycle used to measure progress toward the ultimate goal. They serve as signal posts for a project‘s start or end date, external reviews or input, budget checks, submission of a major deliverable, etc. A milestone marks a significant event or a branching decision point within a project, such as beginning or end dates for project phases, stakeholder approval, key deliverables, meetings, or events. For example, the launch of a product can be broken up by critical events like final design approval or the product arriving at the warehouse for shipping. Project management milestones should mark the four phases in the project life cycle: initiation, planning, implementation, and closure, and can be as simple as placing the final product order or signing off on cover artwork for a magazine launch.