Why to-do lists stop working

Updated 2026-09-12

The short answer

A plain list has no ordering discipline, so it defaults to the order things arrived in. That ordering is called first-in-first-out, and in scheduling theory it is not merely mediocre — it is the one discipline known to be bad for essentially every objective.

A list also has no limit, so it grows faster than any day can absorb. It ends up recording your decisions rather than helping you make them.

The convoy effect

First-in-first-out has a specific, named failure: the convoy effect. One long item at the front holds up every short item behind it, and total waiting time across everything goes up sharply.

You have watched this happen. One awkward task sits near the top of the list. It is not urgent and not especially important, but it arrived first and it is there. Four things that would each take ten minutes sit behind it, and the day ends with none of them done and the awkward one untouched as well.

Nobody chose that. The list chose it, by having no opinion.

What a list cannot do

It cannot say no. A list accepts every item at equal weight, which means adding to it costs nothing at the moment of adding — and everything later, distributed invisibly across the week.

It has no notion of capacity. Twenty lines and four hours coexist happily on paper. The list will never tell you the arithmetic does not work; you find that out at six o'clock.

It cannot distinguish urgent from important, so the loudest item wins by default. This produces starvation — low-priority work never running because higher-priority work keeps arriving. The important thing is not forgotten. It just never reaches the front.

It gets longer than a day, permanently. Once a list exceeds what a day can hold, it stops being a plan and becomes a record of everything you have not done. At that point opening it costs something rather than giving something.

Why this is not about discipline

It is worth being direct here, because most writing on this subject is not.

The failure modes above are properties of the ordering rule, not of the person following it. First-in-first-out produces convoy effects in computer systems that have no willpower to lack. A queue with no priority discipline starves its low-priority work whether or not anyone involved is trying hard.

If a plain list stopped working for you, the list was doing what a plain list does.

What actually fixes it

Not a better list. A limit and an ordering rule — the two things a plain list lacks.

1. Write everything down first. Keep the full list. It is genuinely useful as a record, and you cannot choose between things you have not seen. It is just not a plan.
2. Take a small number from it for today. Three is a practical figure. The constraint is what makes it a decision rather than an intention.
3. Give each one a duration. A line without a time is a wish. The estimate does not need to be accurate; it needs to exist, so that afterwards you can compare planned against actual.
4. Leave the rest visible and unchosen. Not deleted. In scheduling terms this is aging — work that cannot run now moves up for next time. Nothing is lost by not being chosen today.

That is the whole of the Top 3 method, and it is what the long list becomes useful for: the pool you choose from, rather than the plan itself.

One thing worth keeping from the list

Capture. Writing things down as they arrive genuinely works, and it is the half of the habit that is not broken. The break happens when the capture surface and the plan are the same object.

Keep capturing. Then choose separately, once a day, from what you captured.

Where to go next

• How to prioritise your tasks — the three problems and which method fits each
• The Top 3 method — the limit and the ordering rule in full

Using this in Decide One

Decide One keeps the two surfaces apart on purpose. Everything competing for the day is visible; what you chose for today is bounded and separate, and the bound is enforced rather than suggested.

A line you did not finish is unfinished. It is not marked failed, and a day you did not open is not counted against you.

Open Decide One — free to use, with no account. Nothing you write leaves your device.