I'd prefer to have sprints that last 3-4 weeks, but customers don't want to adopt new feature/function every 3-4 weeks. Existing customers are conservative and, once we meet their minimum bar for features and capabilities, they like to remain on a stable release for much longer than 4 weeks. Even a 3-month cycle would be pushing it for them.
On the other hand, newer customers tend to have more feature requests, and are willing to follow sprints. But this willingness dissipates after we've met their bar.
How do you balance the need for rapid sprints with the customer's conservative view of application change?
I'm particularly interested in SaaS scenarios.