Dependencies are a fantastic way to indicate the order in which tasks or project phases should be completed.
Dependencies can be set on the Task or Milestone level.
How Task Dependencies Work
A Task dependency can be set from within an open Task.
When a Task is set as dependent on another Task, it will show a padlock icon over the Complete tickbox as well as a caution tape style header. This header will also indicate the dependency set.
Tasks locked based on a dependency can be edited and updated, but not completed, until the Task on which it is dependent is completed. Those assigned to Tasks that are unlocked based on the dependency being completed will be notified that this Task is now available.
Cascading Due Dates
When a Task has another Task dependent on it, start and due dates will change in bulk by the same amount of days. In the below example, the Task Information Architecture is dependent on the Task Kickoff call. Note that, while this example shows these Tasks as part of a Milestone on a Roadmap, Tasks do not need to be in Milestones to cascade.
When the due date of Kickoff is extended, the start and due dates of Information Architecture are moved by the same amount of days.
This effect can take place through multiple Tasks. In the below example, each Task is dependent on the last (Page Content → Gather Requirements → Information Architecture → Kickoff.) Changing the due date of Kickoff call will cause all of these Tasks to update their start and due dates in a cascade. This is called a Dependency Chain.
Note that cascading is only based on the changing due dates, so you can start Tasks before the Task they are dependent on is completed.