Retention · AI personalisation

Turning a tracker into a habit

New owners were active for a few days, then drifted. We built AI-generated goals, streaks and timely nudges into the Sportstech app, and defined retention carefully enough that I could trust it when it moved.

Company
Sportstech
Role
Product Manager
Timeline
2025–26
Team
Design, Engineering, Data Science, Growth
North-star
30-day retention

At a glance

01 Problem

Users were very active in the first days after purchase, then dropped off between weeks two and four.

02 Insight

They didn't lack intent, they lacked a target. Without one, the app was a tracking tool, not a motivator.

03 Solution

AI-generated 7-day, 14-day and monthly goals, streaks on the home screen, and nudges before someone drifts away.

04 Result

30-day user retention +32% and workout completion +28% within six weeks of launch.

You're in the 30-second version. The full story covers how retention was defined, the honesty check and the guardrails.
01 Context

Our best-selling machines had a week-two problem.

Walking pads and treadmills were Sportstech's best sellers and the devices people used most through the app. The retention data had a clear shape: very active for the first few days after purchase, then a significant drop.

My KRA was 30-day retention. The question wasn't how to get people to try the app. It was how to still have them in week four.

where we lost people
Fig. 01Weekly activity after purchase. Illustrative shape · not measured values.
02 Problem

People bought with good intentions. The app gave them nothing to aim at.

Momentum faded in week two

A new machine carries the first few days. After that, nothing gave people a reason to train today.

No clear target

Users could see what they'd done, but not what “good” looked like this week.

A tracker, not a motivator

The app recorded activity faithfully. It never asked for any.

03 Insight

Intent wasn't the problem. Direction was.

“They didn't lack intent. They lacked a target.”
— Synthesis from user interviews

When we spoke to users, most had bought the machine meaning to use it. After a week or two they lost momentum, because nothing told them what to do next.

That reframed the brief. Instead of just tracking activity, help users build a habit.

04 Solution

Goals the AI sets for you, streaks you can see, and a nudge before you drift.

AI-generated goals

Personalised 7-day, 14-day and monthly movement goals, built from onboarding info and early activity.

Streaks & progress, up front

On the home screen, so users see how they're doing against their goal every time they open the app.

Nudges at the right moment

With our GTM integration, falling behind or going quiet triggers a reminder before the user drops off.

Guten Morgen, Lena Day 4 of 7
3of 5 walks
Your goal · set by AI 5 walks this week On pace
6-day streak
Today's suggestion
25-min walk · 2.3 kmStart
Goal horizon
This user is…
How the goal was set
  • OnboardingGoal: lose weight, move daily
  • DeviceWalking pad
  • Week one4 walks · avg 28 min
  • AI goal5 walks this week

Rule — the tick on the ring is where you should be by today. Fall behind it and a nudge goes out before the streak breaks.

Fig. 02Switch the horizon and the user's state. The goal is sized from what this person already did in week one, and “falling behind” triggers a nudge while there's still time to recover. Mock-up; user and values are illustrative.
05 Measurement

I defined retention so it couldn't flatter me.

“Retention went up 32%” means nothing until you say which cohort, which window and why. Before we argued about whether it moved, I wanted the team to agree on what it meant.

Metric definition30-day user retention
Definition
The resume reports a 32% improvement in 30-day user retention. Reported absolute rates: 28% before, 37% after (about 32% relative lift).
Cohort
The resume does not specify the cohort denominator. The index chart communicates the relative lift only.
Window
The reported result was observed within six weeks of launch.
Honesty check
Illustrative definitions: the demo below compares day-30, bracket and rolling retention; it does not establish which definition produced the reported 32% lift.

Why not “active on day 30”?Nobody works out on a fixed calendar day. If I measured day 30 exactly, I'd mostly be measuring which weekday day 30 landed on.

Who counts as retained?

5/ 10 retained

Tap a row to see why that user counts, or doesn't.

Fig. 03Ten example users, one dot per workout day. Bracket and rolling disagree about individuals (U03, U04, U08) but should move together across a cohort. In our launch cohorts, they did. Example users, not real data.

Why 30 days, not 7 or 90

It maps to money

The subscription billed monthly. Zero workouts in a month meant no renewal, almost a straight line. D30 was our closest leading indicator of revenue.

It's where the drop was

People fell off between weeks two and four. D7 would have shown almost nothing.

It's iterable

D90 is the truer test of a habit, and we tracked it. But one learning loop on D90 is a quarter.

D30operates

The number we steered by, cohort after cohort.

D90keeps us honest

The slower check that the habit actually stuck.

Six weeks is a long time to wait for one number

The first full D30 result arrived about six weeks after launch: the first week's users needed their full 30 days, plus a few days of measurement lag. That's one complete cohort, not a settled result. Until then I watched three leading indicators. They moved first, which is what gave us confidence early.

  1. Week 0

    Launch

    Goals, streaks and nudges go live for new purchase cohorts.

  2. Week 1

    % setting a goal in week one

    Are people accepting an AI goal at all?

    Moved first
  3. Weeks 1–2

    Streak continuation rate

    Once started, do streaks survive the second week?

    Moved first
  4. Week 2

    Week-two retention

    The earliest point the old drop used to show.

    Moved first
  5. ≈ Week 6

    First full D30 cohort

    Launch + 30 days + lag. Then cohort after cohort.

    +32% retention
Fig. 04What I watched while the real number was still cooking. Leading indicators are directional; the reported 30-day retention result is a 32% relative lift.
06 Results

Retention moved, and the honesty check moved with it.

+32%30-day user retention lift
+32%Relative lift within six weeks of launch
+28%Workout completion rate: people finish more when they're working toward something

Read the chart - 28% before and 37% after are the reported absolute rates, an increase of 9 percentage points and approximately 32% relative lift. The interactive definitions demo is illustrative.

07 Guardrails

It's easy to win retention by annoying people. So I named the counter-metrics first.

Hard guardrail

Notification opt-outs & uninstalls

The nudges were the risky part. Irritate people into turning notifications off and you lose every future re-engagement channel, while retention looks fine on paper.

Watched

Support tickets & store reviews

If we were nagging, it would show up in reviews before it showed up in any dashboard.

Health check

Goal completion rate

Goals that are too hard make people fail and feel worse. If completion fell too low, the goals were wrong, not the users.

08 What I learned

A tracker tells people what they did; a goal tells them what to do next. And a retention number is only as good as its definition, so I write it down before I look.

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