One interesting thing I've heard over the last years (and again the other day) is that a lot of teams that have implemented Scrum and have become very successful with Scrum often end up with a feeling that iterations are unnecessary. Some teams take the leap away from Scrum and starts working in a more flow based manner like Kanban and it turns out it works even better for a lot of teams. So why bother with Scrum and not go directly to Kanban if it is better? Well neither Scrum nor Kanban is better than the other. Different times requires different things. Time boxing things is a good way to bring order to chaos and getting things done.