Planning fallacy
What it means
The planning fallacy is a well-documented bias, described by Daniel Kahneman and Amos Tversky, in which people underestimate how long a task will take even when their own experience says otherwise. We picture the best-case version of the work and forget interruptions, dead ends and everything else going on that week.
How to use it
Base estimates on how long similar tasks actually took, not on how long this one should take. Add a generous margin to anything new, plan fewer tasks per day than you think you can manage, and compare your guesses with reality once a week.
Try it: what you write, what LifeOS does
- “wednesday at 3pm start the client proposal” → An appointment on Wednesday at 15:00 with a reminder: an early start leaves room for the time you did not plan for.