I worked for five years at a shop where a few years in we started pair programming aggressively. One of our most experienced engineers was really into XP and agile work (in the “purer” meaning of the term). He often suggested pairing when thorny problems came up, and eventually it spread. It often took half or more of the available time for programming each day. That was by far the best working environment I’ve been in. The team was excellent and it seems like we all improved in our skills when we started doing it more. We cut down on how long it took to get in while managing to produce better code. It made planning features and adjusting to unforeseen snags in plans so much quicker. I can’t emphasize enough how much of an impact it made on me as a developer or how much I miss it.

The biggest downside to me was that it forces a level of engagement exceeding the most heads down solo work I’ve done. I’d come home and feel mentally exhausted in a way I didn’t usually.