Going to the dentist is not a task

"Dentist, Tuesday, 3pm" turns up in a lot of task lists. It is something that has to be done, so it goes with the other things that have to be done. That is a reasonable instinct, and it causes a specific and avoidable problem.

The test is not importance: it is whether the time is yours

An event happens at a time somebody has already fixed. There is usually a place, often other people, and if you are not there at that moment it does not happen. Think of the dentist, a flight, a standup or a haircut.

A task is work you could do at nine in the morning or four in the afternoon and nobody else would notice the difference. Write the report, renewing the insurance, or fixing the failing test. Each has to get done, and when it gets done is still a decision you hold.

None of this is about how important the thing is. Renewing the insurance may matter far more than the standup. Importance decides which of your hours a thing deserves; this decides whether the hour is negotiable at all.

Why the difference stops being about tidiness

On paper, a list is a list. The moment anything schedules on your behalf, the two kinds get handled in opposite ways, and the mistake gets expensive.

A scheduler reads your calendar to find out when you are busy, and writes blocks of work into what is left. That is the whole mechanism. So an appointment that lives in your task list is not busy time. It is invisible. Diarized will look at Tuesday afternoon, see nothing there, and book an hour of deep work at three o'clock, on top of the dentist.

The second half of the problem is the mirror image. Handed a task called "dentist", a scheduler treats it the way it treats every task: as something movable. It will find it a slot, and the slot will be wrong, because the one fact that mattered (that this happens at three, not whenever there is room) was never something the task could carry.

The cases people get stuck on

Most things are obvious once the question is asked. A few are not, and they are the ones people get stuck on.

Four that come up constantly, and where each belongs:

1. "Call the bank before 5pm." A task with a deadline. Nobody is waiting at 4:59; the time is a limit, not an appointment.
2. "Gym, 7am." Either, and you should decide which. If it moves when work gets busy, it is a task. If it is the thing you protect when work gets busy, put it in the calendar and let it be defended.
3. "Prep for the 2pm meeting." A task with a deadline of 2pm. The meeting is the event; the prep is work you can do whenever there is room before it.
4. "Flight at 06:40." An event, plus a task nobody writes down: getting to the airport. Block the travel too, or your calendar says you are free until twenty past six.

The rule of thumb that settles almost all of them: if somebody else would notice you were not there, it is an event. If the only person who knows you moved it is you, it is a task.

What to actually do

This takes about ten minutes once, and then a second of judgement each time something new arrives:

1. Go through your task list and pull out everything with a fixed time and a place. Those go in the calendar.
2. Put them in the calendar you actually keep, the one your scheduler reads and your colleagues see. An appointment in a calendar nobody reads is the same as no appointment.
3. Leave the rest in the task app, and give each one a rough duration. That is the number a scheduler needs and the one most people never fill in.
4. Use due dates for genuine deadlines only. A due date on everything is the same as a due date on nothing.
5. When something new arrives, ask the one question: is this time mine to move?

What you get back

Your calendar becomes an honest record of what is already spoken for: the commitments you have made to other people and to fixed reality. Your task list becomes everything that is genuinely still yours to arrange. Those are two different questions, and a single list answers neither well.

It also makes the scheduling itself boring, which is the goal. Diarized works around what is on your calendar and fills the gaps with what is on your list. Get the sorting right and that is all it has to do.