Why it works
Deciding what to do costs something, and it costs it *before* you've done anything. An unallocated afternoon invites a negotiation with yourself that you will usually lose. A blocked afternoon has already had that argument, on Sunday, when you were a more reasonable person.
It also makes over-commitment visible. Seven hours of work does not fit into four hours of blocks, and a calendar will tell you that immediately, whereas a to-do list will happily let you believe it.
Why it collapses
Because reality is not a calendar. A block runs over. Something urgent lands. You get ill. Now the schedule is wrong, and a wrong schedule is psychologically much easier to abandon entirely than to repair — which is the same failure mode as the revision timetable.
How to block without the collapse
- Block half the day, not all of it. The unblocked half absorbs the overrun. A calendar with no slack is a calendar that breaks on contact.
- **Block *categories*, not tasks.** 'Deep work' rather than 'read chapter 7'. Then the block survives your priorities changing.
- Never carry guilt forwards. A missed block is gone. Do not reschedule it into a day that is already full, which is how three missed blocks become a collapsed week.
- Let the system fill the block. Don't decide *what* to review in the block — let the scheduler decide. You're allocating the hour, not the content, and that's a much easier prediction to get right.