An essential element of agile development is rhythm. As with musical composition where there are different levels of periodicity in the same passage of music, an agile development approach has nested levels of rhythm that serve different needs and interleave to form an efficient, vibrant software development approach.
The build automation system is the metronome of the software engineers. It sets the pace for code submissions, defect resolution, unit testing, peer code integration and more.
Weekly feature drops are the metronome for quality assurance. Stabile delivery of weekly features drive the test organization.
Sprints are the metronome of the product development team. They provide high-level integration points, usability analysis and feedback, and project visibility.
The highest level of periodicity is the release. It is the synchronization point for the entire organization with the customer.