I'm familiar with Plentyoffish and his 10 hours/week. However, one has to be careful with Markus Frind's self-reported "hours worked" because many people who a

I'm familiar with Plentyoffish and his 10 hours/week. However, one has to be careful with Markus Frind's self-reported "hours worked" because many people who are passionate about their projects don't count all related tasks as "work". He's probably not lying but outsiders auditing his time with a hidden camera may not conclude it to be just 10 hours. Also, his "10-hours" seems to describe his steady-state at the 5-year mark and not what he was doing in his first 6 months learning ASP.NET. To put 10 hours a week in perspective, think of creating a web startup and trying to discipline yourself to work less than five 2-hour days because the Plentyoffish guy did it. It's not hard to imagine that a single SSL misconfiguration or typo in an XML config file could have you chasing a mystery bug like that for 12 hours straight. Or an unexpected spike of traffic has you scrambling in the AWS control panel but the issue cascaded to a bunch of other processes that takes days to get things back under control. Or your initial customers want a new feature but your "programming budget" is 10 hours of programming time. Stack just a few of those unexpected crisis together and all of a sudden you're already at 50+ hours for the week. A startup is an endless barrage of those unexpected fires hitting you relentlessly. As for Trello, as far as I know, it's not profitable yet (which some folks consider a factor for "success"). Also, the "we believe 40 hours" may be a sentiment J Spolsky espouses for his workers but he (the founder) may not be necessarily constraining himself to that.