Abstract
JustFit is a no-equipment, wall-pilates-style workout app with 12M+ installs. Its own long-time subscribers are turning against it — not over whether the workouts work, but over a subscription flow that keeps charging people who tried to cancel, and a shrinking exercise catalog for those who already paid for the full one.
Background
For years JustFit - Lazy Workout has sold bodyweight/no-equipment workouts and personalized plans on a subscription model.
What it does
Bodyweight and wall-pilates workouts with a personalization step for goals, injuries, and available equipment, tracked with a daily progress log.
What changed
Nothing announced overnight, but two things have eroded trust over time: the exercise catalog long-time subscribers had access to has visibly shrunk, and the billing flow increasingly charges people who tried to cancel or never subscribed at all.
Why it is soft
The most damaging reviews come from people who say it worked for years — real weight-loss results, not a broken workout engine — and they're leaving over billing and catalog changes, not because the exercises stopped helping them.
Strengths
A subscriber willing to write a paragraph about losing 30lbs over 6 months, then cancel over a shrunk catalog, is proof the core product works — that's a testimonial an incumbent gets to keep, and a new entrant would otherwise spend years earning.
Proven results
Real before/after stories in the reviews, including one describing a drop from 127kg to 75kg over two years using the app at home.
Large, proven audience
12M+ installs is evidence the no-equipment/lazy-workout niche has real demand, not a market a new entrant has to create from nothing.
I've been using this app for two years, and it has completely changed my life. I started at 127 kg, and today I'm 75 kg and still making progress. It gave me the confidence to exercise at home before I was ready to join a gym.
Market gap
The recurring complaints, grouped into named clusters, most-common first:
Charged without real consent
By far the largest cluster: charged after a trial cancellation the app itself confirmed by email, charged an annual fee the user never signed up for, or locked into a new plan by a single misplaced tap with no easy way back.
Injuries and equipment gaps ignored
Users can flag only one injury when they have two, can't swap out a flagged exercise instead of just skipping it, and get exercises assigned that directly contradict what they told the app they can't do.
Catalog quietly shrinks for paying subscribers
A smaller cluster, but the single most-upvoted complaint in the app's reviews: a multi-year subscriber describes the exercise catalog they originally paid for narrowing to a handful of workouts with no notice.
I kept seeing this ad and it looked great. finally paid for the 12 week plan expecting to be able to use justfit. boy was i wrong. when I hit pay, I got an error message saying I wouldn't be charged. checked my bank account and the charge was right there. I got no confirmation email, no personalized plan, nothing.
Im very disappointed with the recent changes. For years I loved this app, lost 30lbs with it in 6 months back when they had the full catalog of exercises. Then imagine my disappointment when everytime I open the app there are less and less options until finally I opened the app one last time to see theyre down to like 5 workouts.
- Never silently reduce what an existing subscriber already has access to. Grandfather the catalog they subscribed for, or announce a change clearly and let them opt out before the next renewal.
- Honor injury and equipment flags exactly, and allow more than one. Swap out a conflicting exercise automatically instead of only offering to skip it.
- Make a confirmed cancellation actually stop billing. No charge after a cancellation email, and a visible next-charge date inside the app at all times.
Build complexity
Estimated, not derived: one developer, part-time, no funding and no paid acquisition. The heaviest lift here is content, not engineering — a broad-enough exercise library to personalize against.
| Workstream | Weeks |
|---|---|
| Exercise content library (no-equipment, multiple skill levels) | 3.0 |
| Personalization engine (goals, injuries, equipment) | 2.0 |
| Progress tracking + streaks | 1.5 |
| Billing: honest trial, self-serve cancel | 2.0 |
| Polish + store listing | 1.5 |
| Total | 10.0 |
Expected revenue
Assumes a $9.99/month subscription, reached without paid acquisition inside a category already searched by millions.
| Month 12, monthly | ||
|---|---|---|
| Installs | 50,000 | |
| Activated | 20,000 | 40% |
| Retained 30d | 5,000 | 25% |
| Paid | 750 | 15% |
| Revenue | $7,500 |
Biggest challenges
Producing a broad-enough exercise library alone, and getting injury/equipment personalization genuinely right — a wrong recommendation for someone who flagged a physical limitation is a safety and trust risk, not just a UX nuisance.
Content production without a team
Filming or animating a wide, credible exercise catalog across skill levels is real, ongoing work for one part-time developer, not a one-time build.
Getting personalization right, not just present
The complaint above isn't that customization is missing — it's that it's ignored, which means correctness, not just the feature existing, is what earns trust back.
AI angle
Something already asked for in market_gap — real, correct injury/equipment substitutions — is markedly cheaper to build with AI than by hand-authoring every combination.
Without AI
Manually writing safe substitute exercises for every combination of goal, injury, and missing equipment — months of plan-authoring before the library feels complete.
With AI
An LLM proposes and validates safe exercise substitutions from a smaller base library against a user's flagged injuries/equipment, turning "add another combination" into a data and prompt problem instead of a rewrite.
Conclusion
Build it. A 12M-install audience with proven results is actively souring on the incumbent over billing trust and a shrinking catalog, not over whether the workouts work.
10 weeks
Time to v1
$9.99/mo
Honest trial, self-serve cancel
$7,500
Revenue at month 12
286
Upvotes on the top complaint alone