Most people take rest reactively, once depletion has become obvious. The reactive approach reliably produces worse recovery than a scheduled one, for reasons that have little to do with discipline.
The signal that triggers rest is unreliable
Fatigue is a poor gauge of accumulated load, since it is strongly influenced by interest, novelty and immediate demand.
An engaging project can mask substantial depletion for weeks, and the tiredness becomes apparent only once the engagement ends, which is often after a deadline rather than before it.
Waiting for the signal therefore means waiting for something that arrives late and arrives most strongly at the point when recovery is hardest to arrange.
Depleted judgement plans depleted recovery
Deciding what would actually restore you requires planning, and planning is among the first capacities to degrade under sustained load.
Which is why exhausted evenings default to whatever requires no decision, and why people frequently report that their time off did not help.
Decisions made in advance, when capacity was available, produce better recovery than decisions made in the state the recovery is supposed to address.
Booked time survives competition
Unscheduled recovery competes with every other demand on a diary and loses, because it has no fixed claim and can always be moved.
A block already in the calendar is defended by the same mechanisms that defend a meeting, which is to say by the awkwardness of moving something already agreed.
This is the ordinary observation that people keep commitments made to others more reliably than commitments made to themselves, applied deliberately.
Regular small recovery outperforms occasional large recovery
Athletic training programmes schedule easier periods before performance declines rather than after, because recovery taken early prevents the decline that recovery taken late has to reverse.
The same asymmetry appears in cognitive work: short regular breaks sustain output better than a long break following a long depletion.
A single annual holiday is consequently a poor instrument for a load that accumulates weekly, whatever it does for the weeks immediately around it.
The limits of scheduling
None of this works where the load itself is unmanageable, and a scheduled hour does not offset a genuinely excessive workload or unpredictable caring responsibilities.
Scheduling is a way of using available recovery well, not a way of manufacturing capacity that does not exist.
Where exhaustion persists despite adequate rest, the question shifts from scheduling to causes, since persistent fatigue has medical explanations that no amount of diary management addresses.