Seeking a client's still work though, nobody's working all the time. At least, if you're reducing sleep so that you can spend more waking hours on billable work, you should probably take a step back!

And I assume the starting point, 5h on $3, was an exaggeration. There's time for saving money, and there's money that's worth the time to save. My point really is that 5h doing non-work hobbies, spending time with family, or whatever, isn't a 'cost'. Not even necessarily an opportunity cost, since for that there had to be abundant supply, that doing it now doesn't mean you're not doing it next week, that there's always more already lined up 'for free'.