digest
Short Summary
Main recommendation: Replace your to-do list with your calendar, scheduling every task into a specific time block based on your estimate of how long it will take, while leaving about 50% of each day open for unexpected work. Sam Corcos argues that the list is the wrong constraint, since a to-do list can hold infinite items but your calendar holds only finite time. Email works the same way: schedule replies instead of leaving messages sitting in your inbox as an undifferentiated stack.
Key Points
- The core problem: people add items to a to-do list without a time limit, then find the plan fails when they try to fit everything into their actual week.
- Recurring blocks for high-volume work, such as at least two hours a day for email, should be locked in first so they cannot be displaced by new tasks.
- Slack time protects the schedule: when one unplanned task breaks a tightly packed day, it cascades into a chain of rescheduling across future weeks.
- Estimation improves with practice: retroactively updating the calendar with how long tasks actually took calibrates future estimates. Corcos says he now leaves about 25% open, up from the 50% starting point.
- Closing the loop with others is part of the method: telling a requester the scheduled delivery date means you can later move it with notice rather than dropping it silently.
Details Worth Noting
- Concrete instructions:
- Take every item from your to-do list and assign it a date, usually this week or next, and block the estimated time on your calendar.
- Start by keeping about 50% of each day unscheduled to absorb interruptions.
- Set recurring blocks first for ongoing work, such as two hours a day for email, then fit project tasks around them.
- For email, open each message, estimate how long the reply will take (for example, 30 minutes or an hour for a substantive write-up), mark it done, and place a link to the message in the calendar slot.
- When a new task arrives, ask when it is needed, find an open slot before the deadline, block the time, and confirm the delivery date with the requester.
- Each week or session, retroactively note how long tasks actually took and use that to improve future estimates.
- The method is adapted from manufacturing, where slack in an assembly line lets it absorb disruptions without breaking downstream steps.
- Corcos notes that he now estimates task duration with roughly 90% accuracy after years of practice, so the 50% buffer can shrink over time.
- A worked example: a memo request with a Wednesday deadline gets a two-hour block on Tuesday, and the requester is told it will arrive by Tuesday night.
Bottom Line
Your calendar should be your task list. Once every task has a time slot, the anxiety of an ambiguous backlog disappears and you can see clearly what you can realistically commit to.
