One question, one answer.

In most cases it is the range of motion: a rep only counts if the movement goes all the way, and stopping halfway is the number one cause of a lost rep. Also check that you are fully in frame and that the light comes from the front rather than behind you. Each exercise page states exactly what Orusta looks at to validate.

Yes. Above a certain cadence, the smoothing that ignores shaking is switched off, precisely because it used to swallow reps when things got fast. A fast set is counted as accurately as a slow one.

Sixteen, across fitness and pilates, from push-ups to scissors and jump rope. The full list, with the technique and how each one is counted, is on the exercises page.

From the deletion page on this site: you enter your address and we send a confirmation link. Permanent deletion happens 30 days later, and you can cancel it any time during that period by signing back into the app.

It is described in the privacy policy: what we collect, why, and how long we keep it. You can withdraw your consent from the app settings.

From your App Store or Google Play account settings, like any other subscription. It takes effect at the end of the current period, and you keep your benefits until then.

The benefits stop: a challenge entry costs a ticket or an ad again, the plan and the diet close. Everything you already earned stays yours, carats included, along with everything you bought.

The deadline is set when the challenge is created, by whoever starts it: there is no fixed duration. The time left is shown on the challenge, and once it runs out the leaderboard is final.