Why five questions a day, not one and not fifty

The number of daily questions in Duoheart is five. It looks arbitrary, and people ask about it more than almost anything else in the app, so here is the reasoning.

One question is a coin toss

We started with one. It is the elegant version: one question a day, carried in your head from morning to evening, answered when you both have a minute. On a good day it works beautifully.

The problem is the other days. A single question either lands or it does not, and there is no second chance until tomorrow. If today's question is about childhood holidays and one of you had a rough childhood, the day is a miss. If it asks about future plans on the evening of an argument about future plans, it is worse than a miss. And some questions simply arrive on the wrong sort of Tuesday, when one of you has had eleven hours of meetings and can produce nothing but a shrug.

With one question, a miss is the whole day. We watched that happen enough to know it was a design flaw and not bad luck.

Fifty questions is homework

The obvious fix is more questions, and more questions has an obvious failure mode of its own. Once a set gets long enough, answering stops being reflection and becomes clearing a list. People start writing shorter. "Yeah", "same", "good one". You can feel the moment in your own writing where you switch from thinking to processing.

A long set also breaks the promise that the app is finished with you in a few minutes. Anything that reliably takes twenty-five minutes on a weeknight will be skipped on the busy nights, and busy nights are most nights. An app you skip four days a week is not a habit, it is a source of guilt with an icon.

The right length is one you can finish on your worst evening, not your best one.

What five gets you

Five is enough for a mix. On any given day the set spans different kinds of question: something light and easy to answer, something about the last day or two, something about the two of you, sometimes something that asks for a bit of courage.

That mix is the actual mechanism. It means a hard day is not wasted, because there is always a question you can answer honestly even when you have nothing deep left. And it means an easy day is not shallow, because there is always one question with some weight in it. The set has a floor and a ceiling, and one question can only have one of the two.

It also gives the day a shape. The lighter questions get you writing, and once you are writing, the harder one is much easier to face than it would have been cold. Anyone who has tried to start a difficult conversation from silence knows the difference.

Five is also a number you can finish in a few minutes without rushing. Long enough to feel like something happened, short enough that neither of you is looking for the exit.

Why we cap it instead of letting you add more

The most requested change to this is a slider: let each couple pick how many questions they get. We keep saying no, and it is worth explaining why, because it is not laziness.

The cap is doing work. When the number is fixed and small, every question in the set has to earn its place, which forces us to be ruthless about quality. If the set could expand, the pressure to be ruthless disappears, and the average question gets worse for everybody.

The cap also protects the couple with the busier schedule. In most pairs one person has more time and energy for this than the other. A slider quietly becomes a negotiation about how much the relationship deserves, which is a horrible thing for an app to introduce into a Wednesday. A fixed five means nobody has to ask for less.

And the same set for both of you is what makes the blind answering work. Both partners answer the same five, separately, without seeing each other, and everything unlocks at the same moment. That mechanism needs a shared, fixed set.

When five is not enough

Sometimes a question opens something up and five is nowhere near enough. That is what the thread under each answer is for. Once the answers unlock, each one becomes its own private conversation, and that conversation has no limit and no timer. The five are a way in, not a ration.

There is also today's topic, a single conversation starter for the day, for the evenings when you want something to talk about rather than something to answer.

So the honest summary of the number: five is the smallest set that still contains a good day and a bad day, and the largest set that still finishes before either of you gets bored. We tested our way to it rather than reasoning our way to it, and we would change it if the evidence changed.