Separate the planning session from the execution day

Do your planning in a dedicated session, never on the day you intend to start.

Why it works

Planning immediately before execution compresses deliberation under time pressure, which amplifies optimistic anchoring: you unconsciously plan for the ideal scenario because anything more conservative feels like giving up before you start. A separate planning session removes the emotional urgency, allows you to consult your reference class calmly, and lets the plan sit overnight — a form of incubation that often surfaces overlooked obstacles. This is also a form of "cool-state" decision-making: plans made in a neutral state are more realistic than those made in the motivated state of imminent action.

How to do it

1. Designate a weekly planning session (e.g., Sunday evening) that is decoupled from any execution day.
2. During that session, review last week’s actual vs. estimated times before building the new plan.
3. Set next week’s schedule fully, then close the planner until execution begins.
4. On execution days, run the plan; save replanning for the next planning session unless something genuinely breaks.

Evidence

Hot vs. cold state decision-making research (Loewenstein, 1996) shows that decisions made in a neutral state are more considered and less impulsive than those made in an affective state. Direct evidence for planning-session separation is mechanistic rather than trialed. (mechanistic)

The hot/cold distinction is robust; its application to time estimation specifically is plausible but extrapolated.

Sources

• Loewenstein (1996), Out of control: Visceral influences on behavior, Organizational Behavior and Human Decision Processes

Common mistake

Treating planning as a task to dispatch quickly before getting to the "real work" — fast planning is the source of most of the optimism bias.