Buffer and overflow blocks

Schedule empty buffer time to absorb overruns and the unexpected.

Why it works

Plans fail not because the tasks were wrong but because they were packed end to end with no slack. A buffer block absorbs the inevitable overruns and surprises, so one delay doesn’t cascade through the whole day and force you to abandon the schedule entirely.

How to do it

1. Leave 25–50% of the day unblocked or in explicit buffers.
2. Place buffers after high-variance tasks (meetings, creative work).
3. Use buffers for overflow or genuine rest, not as more task space.

Evidence

Buffering is a direct countermeasure to the planning fallacy — the robust tendency to underestimate how long tasks take and to ignore the chance of interruption. (observational)

How much buffer is enough is individual; the finding is that some explicit slack outperforms a fully packed plan.

Sources

• Buehler, Griffin & Ross (1994), the planning fallacy, J. Personality & Social Psychology

Common mistake

Filling every buffer with "just one more task", which removes the slack and guarantees the first overrun blows up the rest of the day.