How long is a scrum sprint?
How long is a scrum sprint is a question that many agilists differ on! 2 weeks, a month, 3 weeks - "man, but we can't even do 6 months!"
I present the problem to my scrum team as part of our commitment and values of the team because each organization has different sequences and outputs that determine their efficiency. For a new team I'll guide their answer to consider when can they successfully deliver an increment of a potentially shippable product? The response is generally "I reckon I could..." and then QA says "yeah and the following sprint we'll test it"! And then I'll challenge them to either complete within the month or extend it to two - to reinforce that quality is no longer the forgotten superannuation - you invest now and always.
More often the response after that is " but we can't cause" " we've never done that" and other linear paradigm beliefs that prevent teams from being agile. And to finish off the journey - so they create a self-organized sprint plan - I'll "ask if you could deliver in one month, so all we hav to do is flick the go live button, what would it look like? "
They come up with ideas and challenges, & start to solve each others problems. The attitude will sometimes be stringently resistant. At the end I'll summarize what they said into a list of tools, actions, environments. To sum up i'll congratulate them on giving the scrum master the first impediment list and that is my mission to support them to deliver efficiently so we need to cut the crap out and build the reality ourselves.
It's not so much the sprint duration -it's the ability to Provide quality incrementally and continuously. It's about check in points with the business and the drive to deliver together.
If your team is on 6 months challenge them to go quarterly, when they get good at that- go monthly, and so forth until you discover continuous delivery heaven.
For other organizations I'll ad the lean business view to determine the cycles which generally are - Annual - strategy Quarterly - portfolio Monthly - product (performance) Bi-monthly/ weekly sprints
Have fun :)