[arturnt]

An average work day isn't filled with 100% development. You have breaks for lunch, coffee, people asking you questions, meetings, ping pong, etc. For a good workplace a chunk of your time is a social experience like any other. That means if you spend about 2-3 hours a day total socializing, then the 5 hours a day you spend working. For startups, sometimes you have time sensitive releases so that number goes from 5 to 10, but it's still only about 50 hours of actual development per week even though it's 65 with all the other stuff included.

Treehouse has managed to make a 4 hour week work since everyone is working remotely, so that social aspect is not as prominent and consumes less time. For people who have kids spending time for the kids becomes more important than the social experience at work as it should. The 4 day work week all of a sudden makes sense since they have bundled those 3 hours / day of a work social time into one day of a kids time.