It is common to have tasks that need to be completed in a set period of time, but don't necessarily require an equivalent amount of work. For example, you might have two weeks to fix a bug, but fixing it will only take a few hours. Using Fixed Duration, Structure.Gantt helps you estimate the average work required for those tasks and plan accordingly.
When a task's Start and Finish dates are both assigned (either by manual scheduling or by sprint), the task has a Fixed Duration, which means the duration of the task is independent of the work required to complete that task.
When updating a fixed duration task:
- Adjusting the amount of work required for the task does not affect its duration.
- Moving the task's Start or Finish Date will change the duration but not change the work requirement. Instead, the same amount of work will be redistributed across the new duration (see below).
With fixed duration, the amount of work that needs to be completed for a task (it's work estimate) is divided evenly across the the duration when calculating resource usage. So if an issue's work estimate is 10 hours (1d 2h) and the task has a fixed duration of 10 working days, the issue would require 1 hour of work each day.