Treating todos as calendar events is helpful because calendars introduce constraints. A calendar forces you to estimate how long each task will take and then find empty space for it on a 24 hours × 7 days grid, which is already cluttered with other things. It’s like playing Tetris with blocks of time.

Digital tools designed to enhance our productivity and help us manage information have proliferated over the past two decades. These tools are great for tracking and executing tasks, but less helpful when it comes to figuring out what work we should be doing in the first place.