Usually a milestone is used as a project checkpoint to validate how the project is progressing and revalidate work. Milestones are also used as high-level snapshots for management to validate the progress of the project. In many cases there is a decision to be made at a milestone.
Tavaliselt kasutatakse tähtaegu projekti kontrollpunktidena selle täitmise edenemise hindamiseks (ja vajadusel ümberhindamiseks). Sageli langetatakse tähtaja saabudes mingeid otsuseid.