Earlier quoted context omitted.
Sorry, I must disagree. Two people working 20 hours a week are refreshed, not burned out, have time for educationally side projects, etc. I am in my early 60s and for my whole life I limited my work hours to 32 hours per week, even working for large companies. I had lots of time for educational side projects, exercise, extra time with family and friends, and mediation. My only regret was not perhaps cutting this to l…
Err... 20 hours is really not a lot of work. Some problems, to be solved, require intense work. At 40 hours a week you will hardly feel "burned out".
Someone who works 40 hours, takes regular breaks and keeps a moderate pace, sure. 40 hours of high pace concentrated development work? In the last 17 years of managing development teams, I've had maybe 1-2 people who could sustain that for more than a week or two at the time.