This is something that hit me during my master thesis the first time: I was entirely free to choose my work time, work mode. Since the prof was very hands-off too, only the result after 6 months mattered. That was quite the weird time. But it taught me some pieces about work-life balance and choosing what is 'enough work', as well as giving your brain time off, or time on something else to work through more complex topics and to recharge.

This is also why I honestly enjoy being a salaried employee. My employer buys 40 hours a week from me. Right, some weeks it's 50 and the next week only 30. Some weeks need a machine just executing, some weeks need more careful thought.

I could optimize it for more monetary output, but at the moment it is a predictable, usually not-painful thing with decent monetary output for personally more interesting subjects. I've found appreciation of this.