In knowledge work, when you agree to a new commitment, be it a minor task or a large project, it brings with it a certain amount of ongoing administrative overhead: back-and-forth email threads needed to gather information, for example, or meetings scheduled to synchronize with your collaborators. This overhead tax activates as soon as you take on a new responsibility. As your to- do list grows, so does the total amount of overhead tax you’re paying. Because the number of hours in the day is fixed, these administrative chores will take more and more time away from your core work, slowing down the rate at which these objectives are accomplished.

Slow Productivity, Cal Newport, 56

This! This is why we have so many meetings, too many emails, and a constantly churning Slack chat. Every task comes with its share of overhead tax. The problem is that we don’t account for this, take on too many tasks, and then wonder why we are overwhelmed.

Every task takes more effort than just bringing that task to completion. It requires management (when we don’t get to it or procrastinate), research from the internet, collaboration with peers, and much more. Every task for a knowledge worker is a little project with its own overhead. Taking on fewer is the only way to get them all done.