The more we come to understand the power of rhythm and tempo in any kind of activity the more we understand that the setting of deadlines that do not have a steady rhythm or tempo lacks power to make traction toward any kind of progress possible.
This is why agile project methodology that uses two weeks sprints has such enormous advantage over the traditional waterfall practice of sporadic deadlines that have no ready tempo.
The vast majority of deadlines in projects and planning are not and it is no coincidence given the fact that they do not represent a steady pattern of rhythm or tempo. Steady pattern of rhythm or tempo is something like deciding what's gonna be done every two days or every two weeks or every six weeks. Even within the micro world of tasks, checklists and subtasks momentum is steady activity where we feel we are in a redemptive flow on our way to starting and finishing each of these.
So the question that really drives momentum is the question of how often should we be working on this task or subtask checklist, rhythm and tempo?