I have been freelancing for 20+ years.
Fully agreed with OC, my clients are not paying for me to sit by the desk they're paying for solutions to problems. The more complex the problem, usually the less tapping on keyboard.
I know, some gigs are in fact just showing your face on Skype or in presence, I have come to avoid these regardless of leisure impact.
I'd like to think that, were I not salaried, I'd work only as much as i needed in order to do whatever it was that I wanted to do with the rest of my time - not relax in a way that allowed me to work as much as possible.
Of course, in reality it's a slightly harder optimisation problem than presented, since time is a factor too, and maybe you can't afford to do what you want to do leisurely for 4 days a week, working 3, but it can be done at 3.5 each way.