Knowing when to stop

freelancers operate unconstrained by dress codes and other workplace conventions

Have burned through various systems & schedules in the last seven months of freelancing. The current iteration is to get up at 8am and work through until a bike ride / lunch, then work again until somewhere between 4pm and 6pm, when it's clear that nothing more can done at a decent speed or in good spirit, and then I just quit and forget about work until the next morning.

What's striking to me is how, after all the strange schedules I've tried, the most conventional one, essentially 9-to-5, is the one that feels and works best

Apart from a few months in 1992, I've never had a 9-to-5 job. The novelty has yet to wear off.