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.

tasks should live in your calendar, but that doesn’t mean every calendar event should be a task.

A meeting is a multiplayer calendar event. It is not the same as a task.

To ensure that no other meetings are scheduled during those travel times, you added two “do not schedule” blocks (DNS). These are neither meetings nor tasks. Their only purpose is to avoid conflicts with other upcoming events.

The DNS blocks appear before and after the meeting, but what they really represent is one entire layer of time that stretches from 10:30 to 12:30. Your conversation with Mike is a meeting layer on top of your blocked time layer.

We are now looking at three different types of calendar events, each with their own unique set of properties

Activities. An activity takes place for a prolonged period of time, but only requires your attention at certain points of it — not throughout

Something I never really noticed before is that we only use our calendars to look forward in time, never to reflect on things that happened in the past. That feels like a missed opportunity

My Garmin watch can tell my current level of stress based on my heart-rate variability, but not what has caused that stress or how I can prevent it in the future. It lacks context.

Sleep is another data layer that would make a lot more sense in my calendar than in a standalone app. I already block time in my calendar for sleep (mostly as a DNS-memo to coworkers in other time zones), so why not add sleep quality data directly to that calendar event?

It allows us to shape the future by studying the past.

Even a Spotify layer starts to make sense when you look at it in combination with stress data (which music calms me down?), productivity metrics (which music helps me focus?), or personal activities from the past (nostalgia).

Calendars should natively differentiate between different types of calendar events. Tasks, meetings, blocked time, and other activities should look and behave differently depending on their respective attributes.