Scrum teams depend on finances, sales & marketing, support, and other functions in an organization. They are rarely an independent unit. A Scrum Team needs to coordinate with the rest of the organization and other teams. For example when revising architecture, doing integration test, or introducing new tools. If the surrounding organization has a monthly pulse due to the financial rhythm, and the Scrum teams has a different end /start date of sprints, the organization as a whole risk to be out of step. The same is true if the Scrum teams have different sprint lengths.

The surrounding organization has to learn to respect the teams' sprints and not disturb arbitrary. At the same time we need to support the flow from the organization into the scrum teams in a way so we avoid unnecessary waiting or interrupts.

Centralized sprint lengths can take away some freedom from the team. On the other hand Regular Product Increment and Organizational Pulse should be harmonized to support flow.

Therefore:

Synchronize the teams’ sprints by having the same start/end date at least once a month. Let the organization as a whole follow a monthly rhythm that can harmonize flow for Scrum teams' sprints, as well as for the financial rhythm of the business. Allow teams and departments to choose shorter sprints. For example 1, 2, or 4 weeks sprint length.