Loading
A sprint is a fixed-length period — usually one to three weeks — in which a team commits to a set of work and the scope is protected from change.
The length matters less than the fixedness. A sprint whose scope changes mid-way is a week with a name.
Because switching costs are real and invisible. Work half-done is work not delivered, and a team interrupted three times a week finishes almost nothing while appearing busy.
The protection is also what makes the commitment meaningful. If anything can be added at any point, nothing was ever committed to.
One to three weeks. Shorter for uncertain work; longer when overhead outweighs feedback.
It can, and each time it does the commitment means less. Reserve capacity instead.
Not well. Reserve a proportion of capacity for interrupt work instead.
Half an hour with your own data usually saves reading three of these. The guides will still be here afterwards.