Sprints are the heartbeat of Scrum, where ideas are turned into value.$^1$
They are fixed length events of one month or less to create consistency. A new Sprint starts immediately after the conclusion of the previous Sprint.
All the work necessary to achieve the Product Goal, including Sprint Planning, Daily Scrums, Sprint Review, and Sprint Retrospective, happen within Sprints.
During the Sprint:
<aside> 💡 Note that a Sprint and an Iteration, while similar in Agile, are not the same thing. See this article on how to tell them apart and which is the best for your project.
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Sprints enable predictability by ensuring inspection and adaptation of progress toward a Product Goal at least every calendar month. When a Sprint’s horizon is too long, the goal may become invalid, complexity may rise, and risk may increase. Shorter Sprints can be employed to generate more learning cycles and limit the risk of cost and effort to a more petite time frame. Each Sprint may be considered a short project.
Various practices exist to forecast progress, like burn-downs, burn-ups, or cumulative flows. While proving useful, these do not replace the importance of empiricism. In complex environments, what will happen is unknown. Only what has already happened may be used for forward-looking decision-making.
A Sprint could be canceled if the Sprint Goal becomes obsolete. Only the Product Owner has the authority to cancel the Sprint.