Will Read's blog
An informal survey conducted earlier at Pivotal Labs asked "how often do you rotate pairs on your project?" The answer for the Best Buy Remix team is usually every two days, but three days is the hard stop. It was about the same when I worked on the Palm Pre apps. But back on Mavenlink, we rotated ever single day.
Working for Pivotal Labs is different than any other software shop I know. A big part of this is that it is easy to feel good about the product you're delivering to your client. Another reason is that we constantly challenge our own practices, ensuring that we continue to do the right things for the right reasons.