

3–4 hours of focus time, and another 3–4 hours of passive time where the brain gets to work on its own. Usually this is what a full time job is, so don’t expect to do more after that. (Mundane purely “mechanical” jobs add a bit of variables, let’s disregard those for now. Work is work and it takes its toll)
Those who say they’re active for 8 hours consistently don’t know how to measure time, or they’re super rare outliers, or outright liars. It’s just not sustainable.
The true purity test of a leftist is that they have to like cats