How often should you change pairs?

Question

In the company I'm currently working on, we've been doing pair programming for a while now. In the current project, for the last couple of days, we've been trying to make our pair programming a little better, so we even have a timer now to ensure that the swap between driver and navigator happens often enough.

For changing pairs, we tried to do it in several ways. We tried changing at the end of the week, but found it too long. We tried in the middle of the week but we tended to forget, so we decided to do it daily.

Problem is that there are some stories that take a couple of days, so it's a little cumbersome to do it this way. Then we changed to a "per story" pair changing. But this is just a little uneven because the stories themselves most of the time are uneven as well.

So, simple question:

How often should you change pairs?

Answer 1

Whenever it makes sense to.

From experience, we don't have strict allocated time for peer-programming. It is merely an exercised concept to benefit developers. During allocation of tasks, sometimes it makes sense for two people to tackle the task together. So there's no sense of strict rotation like speed dating.

Answer 2

I guess I'd have to say that we change on a per task basis, but as you pointed out task durations aren't always equal. On average I would say that we change partners twice a week but there's no set day or rule about it. If a pair completes their task and no one else is close to finishing theirs, then they'll just start their next task together as well.

What's good about it is that there is no rut to the week. You're never quite sure when you come in for the day whether you'll be paired up with someone new or not. I kind of like the spontaneity of it.