I notice that when working on difficult creative projects, I usually can’t meaningfully work for more than 4 or 5 hours a day, and most days it’s more like 3. By contrast, when I’m programming or doing other relatively more mechanical work, diminishing returns occur at more like 8 or 9 hours. Sometimes more if the work is somewhat varied, or if it’s very well-specified.
After a few hours of intense creative work in a day, the marginal hour usually starts to feel much more difficult. I’ll have trouble maintaining focus. I’ll notice myself becoming detached and caring less (which can lead to awful persistent knock-on effects!).
This surprisingly low limit is a common trope among writers, who often write in a focused session in the morning, then spend the rest of the day doing other tasks and relaxing. And yet… this is not always true: Some people have extraordinary energy for creative work
While many creatives report doing only a few hours of core work per day, they often gain more effective hours by {working on the weekend}.
Related:
Ericsson et al - The Role of Deliberate Practice in the Acquisition of Expert Performance
Almost without exception, writers tend to schedule 3–4 hr of writing every morning and to spend the rest of the day on walking, correspondence, napping, and other less demanding activities (Cowley, 1959; Plimpton, 1977).
Once you know the shape of real work, you have to learn how many hours a day to spend on it. You can’t solve this problem by simply working every waking hour, because in many kinds of work there’s a point beyond which the quality of the result will start to decline.
That limit varies depending on the type of work and the person. I’ve done several different kinds of work, and the limits were different for each. My limit for the harder types of writing or programming is about five hours a day. Whereas when I was running a startup, I could work all the time. At least for the three years I did it; if I’d kept going much longer, I’d probably have needed to take occasional vacations. ~5~
https://twitter.com/michael_nielsen/status/1411700590661472260?s=20
Mason Curry has a book on the daily work habits of (very successful) writers and artists. And it’s strikingly similar to this - the median seems to be about 4 hours per day of real work, usually in the morning, with a lot of outliers.
Some related references at What Is The Morning Writing Effect? · Gwern.net
Unemployment Part 2 - How to Save Yourself | Applied Divinity Studies
Accept that you max out at 4 hours a day, and make sure you actually hit it every day.
Efficiency is highly overrated; Goofing off is highly underrated. Regularly scheduled sabbaths, sabbaticals, vacations, breaks, aimless walks and time off are essential for top performance of any kind. The best work ethic requires {a good rest ethic}.