Project milestones are key points in a project timeline that signify important stages of progress. They help teams track their advancement and ensure that the project is on schedule. Each milestone typically represents the completion of a significant task or phase, allowing for assessment and adjustments as needed. Milestones are often used in project management methodologies, such as Agile or Waterfall, to provide structure and clarity. They can also serve as communication tools, keeping stakeholders informed about the project's status. By marking these critical points, teams can celebrate achievements and maintain motivation throughout the project lifecycle.