I think for me personally a 4-6h workday on 4 days per week would be optimal. It's enjoyable to actually work together with a team on a product and provide a service which people want to use.
Such part time jobs can be very fulfilling if money is not an issue.
Open source might be the right avenue for this type of freedom. Work on something important like Matrix or something
not in my experience. there are often people around that only do 25-35hours per week... at least in the places I've worked at 'till now.
> Open source might be the right avenue for this type of freedom
with open source, you're always an outside contributor. That might be enough for some - but I doubt that my motivation could keep up long term in that setting.