Decision Fatigue: Why You Feel Exhausted Without Having “Done” Anything Physically

None of these studies points to a magic solution, but they do, quite consistently, point in the same direction.

The first is to reduce the number of trivial decisions we make without realizing it: the more routines and default settings we have for repetitive tasks, the fewer resources we spend on decisions that add no value simply because they are deliberate.
The second is to get pending decisions out of our heads and put them somewhere external and reliable: not because writing something down solves the problem, but because, as Masicampo and Baumeister demonstrated, the mind stops actively monitoring what has been captured and decided elsewhere.
And the third, perhaps the easiest to overlook, is to avoid making the same decision over and over again: every time we revisit a decision we’ve already made, we pay the full cognitive cost all over again, as if we’d never resolved it in the first place.
None of these three principles requires a complex methodology or a specific tool. It simply requires understanding that the mind is not designed to juggle hundreds of open decisions at once, and that much of the exhaustion we feel at the end of the day doesn’t come from what we did, but from everything we had to decide at some point.

— Read on facilethings.com/blog/en/decision-fatigue