I agree that pacing and breaks are important and I didn't mean to imply otherwise. I was offering an alternative perspective to the claim that "most people only have 4 hours of work in them". I just don't think that's true for people who are working on things they find intrinsically motivating. I'm also skeptical of the claim that that 60 hours a week isn't healthy long term, assuming you have the right habits in place. But I'll admit that I haven't really looked into the research on this, if it exists.
