Fair enough, but I suspect most people are not under control of their working schedule. Also, most are supposed to work for at least 8 hours a day. Planning for

Fair enough, but I suspect most people are not under control of their working schedule. Also, most are supposed to work for at least 8 hours a day. Planning for 15+ minutes break every hour, that means a total of 2+ hours break in addition to the 8 hours work. Add the daily commute, and you easily end at 11-12 hours for "business". So I guess this approach makes only sense, if you can afford to do real work for 6 hours, and spend the rest for breaks.