Gantt charts are used to plan and track the progress of a project. It is a graphic timeline that shows the order of activities, time required for each activity, and resources needed for each activity. The main purpose of Gantt chart is to make it easier for people to understand and follow the progress of a project. It also helps in keeping track of what has been achieved and what still needs to be done. However, there are certain limitations with Gantt charts which makes it difficult to use them in some situations. Gantt charts should be used when there is enough time allocated for every task involved in the project and when tasks can be broken down into smaller parts or milestones.