I agree about downside of long work hours. There is a point of negative returns, bugs and rework. Mine is about 45 hours. Productivity counts, not hours. My boss said that I “was the laziest person he ever saw”. Later, he said that I “was producing more than the 2 people that I replaced”. I never had a project fail and my estimates were within 5% of actual, one half-year project was off by only 8 hours. I was once fired for working only 8 hours per day as agreed when I was hired.