Milestones of a Project Management Plan

Any event that is important for a project can be marked as milestone in a project management plan. Milestones help the project managers in tracking the progress of the project at some intermediate points. These events work as check points for the project management plan. These can be measured against the baselines for the time, cost and quality. This helps the project manager in controlling the project. If there is any variance from the baselines, some corrective actions need to be taken to control the project and bring it back to align with the original plan. If the variance is too large and the project cannot meet the initial set baselines even after the corrective actions then the project manager should update the other stakeholders and take their buy-in for making other changes to the agreed project management plan.
Some of the milestones can be imposed by the project sponsor or the other external stakeholders and those are to be met to satisfy the requirements and the needs of the stakeholders.