Scrum is a framework for teamwork, first used for software, created by Ken Schwaber and Jeff Sutherland. Its rulebook, the Scrum Guide, gives every meeting a fixed maximum length, called a timebox. “The Daily Scrum is a 15-minute event for the Developers of the Scrum Team.”
For a one-month work cycle, the planning meeting is limited to eight hours, the review to four and the retrospective to three.