Subtasks are parts of one job
Use a subtask when the work belongs to the parent and would never be scheduled separately — "write the copy", "build the page", "QA the page". The parent is done when its subtasks are done, and progress rolls up automatically.
Dependencies are between jobs
Use a dependency when two independent pieces of work have an order. "Design system tokens" blocks "Rebuild the pricing page": both are real projects with their own owners, one simply cannot start first.
- Blocks — this task must finish before the other can start
- Blocked by — the reverse, entered from the other side
- Related — a link with no scheduling meaning at all
What blocking actually does
A blocked task shows a red marker and cannot move to In progress until the blocker closes — unless you override it, which is recorded on the task. On a timeline, moving a blocker moves everything downstream of it and tells you how much slack you just consumed.
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