They’re called sprints because they’re fast.
Agile development is designed for quality and flexibility. The fact that it’s also highly efficient is a bonus. There’s a huge variance in developer efficiency, even among capable and motivated people, and the combination of Rails and a strong process means that we really get things done.
On the surface, planning out and committing to a one-week sprint is about giving the product owner - the client - some certainty about what they’ll be able to ship. But as a developer, it provides a powerful focus.
Taking this to the extreme, I was able to write Relentless Memory in a matter of hours because I knew exactly what I wanted to build, why, and how I was going to do it. And this was under adverse circumstances: normally my early mornings aren’t good for anything but drinking tea and reading Hacker News while I wait to wake up, but with narrow, clear direction they became highly productive.