How Plan Mode builds a wedding (or trip, or pregnancy) checklist

Most countdown apps stop at days because days are easy. Subtract one date from another and you get a number. You can render that number large, pin a photo behind it, and ship.

Soon. does that too. Plan mode is the layer after the number: a checklist of what to do between now and the date, and a timeline of milestones on the way there, both matched to the kind of event. It is free.

This post is the design note for that layer: what it does, what it leaves out on purpose, and why.

Suggestions written in advance, not generated

When you open Plan on a moment, Soon. suggests a starter plan for its kind of event. There are suggestions for trips, weddings, birthdays, exams, work, holidays, health, a baby, concerts, and sport. Anniversaries and general moments can have a plan too.

The suggestions are written once, ship inside the app, and are the same for every user. We chose that on purpose, and the choice needs some defending.

The alternative is generation: when an event is created, send the event type and date to a server (or an on-device model) and get back a personalised checklist. We considered it and decided against it for four reasons.

1. Generation pulls data off the device. Even with a local model, the design pressure is to give the model more context so the output gets better, and the more context you collect, the weaker the privacy guarantee gets. A list that ships in the app needs nothing from you to appear.

2. Generated checklists are inconsistent. A wedding list written once is the same for every user, so two friends comparing notes start from the same baseline. A generated list might include the rehearsal dinner one time and skip it the next, or add a task that doesn’t exist. We optimise for stability.

3. Writing the lists by hand is slow, and that helps. Writing a good wedding list forces a person to decide whether a task comes seventh or first. A model doesn’t ask that, and the slow part of writing is where the order gets fixed.

4. A written list can be checked. What the app suggests for a wedding today is what it suggests tomorrow, so it can be read, questioned, and fixed.

So every starter plan is a list, written by a person, and the same for everyone. Your own additions go on top of it.

Counted back from the date

The second design decision is that the timeline is counted back from the day you are waiting for, not forward from today.

That lets the same suggestions fit any date in any year. A trip in seven months and a trip in three weeks start from the same plan; only how far away the day is changes. It is also how people think about getting ready. You tell your photographer “two weeks before the wedding,” not a calendar date.

The rest of the app already works this way. The widgets on the Home Screen, Lock Screen, and StandBy show days to go, so time-before-the-day is the app’s native unit, and the plan uses the same one.

The clearest example is a baby. With Premium, a Baby moment gets a guided week-by-week timeline: week 12, the first trimester ends; week 20, the anatomy scan; week 36, pack the hospital bag. Its checklist includes “Pack the hospital bag” and “Install the car seat”. Pregnancy is counted in weeks because that is how people talk about it. It is a planning aid, not medical advice, and the weeks are generic.

Reminders, if you want them

The free version of Soon. sends no notifications. The plan sits on the moment, and the countdown sits on your widgets.

Premium adds reminders for plan items, and reminders for the moment itself 7 days, 3 days, and 1 day before, and on the day. Nothing arrives every morning just to say the number went down by one.

What Plan mode leaves out

It doesn’t restructure your plan. What you add stays where you put it, and Soon. doesn’t reshuffle the list behind your back. If you want the starter plan again, “Reset to suggestions” is there.

It doesn’t share. Soon. syncs your moments through your own private iCloud, to your own devices. There are no shared countdowns between people, so two people planning the same wedding each add it in their own copy of Soon.

It doesn’t optimise. No algorithm watches which tasks you complete and reweights the suggestions. The plan you start with is the plan you get, and any personalisation comes from your own additions.

It doesn’t track you. Soon. carries no ads, tracking, or third-party SDKs, and nothing about which tasks you tick off is sent anywhere. We don’t know what users check off, ignore, or add, and we don’t want to.

Each of these was left out on purpose.

What the plans look like

The Soon. app page shows what a moment looks like in the app, including a trip a week out and a Baby plan week by week.

The suggestions are the author’s judgement, with no usage data behind them. A wedding plan starts earlier than a birthday plan because the slow prep (the venue, the save-the-dates, the fittings) begins earlier. If a suggestion is wrong for your event, add what’s missing and tick off what doesn’t apply.

Beyond Soon.

Most apps that try to do planning end up either (a) too generic to be useful, or (b) so configurable that they need setup work nobody wants to do. A starter plan per kind of event sits between the two: it ships with sensible defaults, takes your own additions, and doesn’t try to learn anything about you.

For a countdown app the engineering is light. A suggestion is a list, and a milestone is a number of days before the date. The hard part is writing the lists well, which is a writing problem more than a technical one.

If you build planning features into a vertical app (workout, cooking, study, project), the same shape works: ship written lists, anchor them to a meaningful zero such as the date, the deadline, or the milestone, count back from it, and stop there. Leave out the generation, the tracking, and the auto-tuning, and ship the list.

Soon. is available on the App Store for iPhone. It is free for up to 5 moments, Plan mode included, with no time limit. Premium adds unlimited moments, reminders for moments and plan items, the weather forecast, daily notes, repeating moments, and Baby mode. More on the Soon. app page.