# Worry Monster vs REM Sleep Tracker

The clearest difference is price: REM Sleep Tracker at Free against Worry Monster's $0.99. REM Sleep Tracker also leads on update cadence (every 2 weeks vs every 27 months). Worry Monster's advantage is in-app purchases (none vs 2) and device support (3 vs 1). On review sentiment and ads there is nothing between them.

REM Sleep Tracker is free to download; Worry Monster costs $0.99 up front. REM Sleep Tracker sells 2 in-app purchases, starting at $9.99 per year. Worry Monster asks for nothing beyond the download.

Worry Monster ships an update every 27 months, REM Sleep Tracker every 2 weeks. Both last shipped on October 24, 2026.

## The numbers

| Metric | Worry Monster | REM Sleep Tracker |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | — | **[4.2 (49 ratings)](https://appshunter.io/ios/app/rem-sleep-tracker/id6446677275/reviews)** |
| Number of ratings | — | **49** |
| Positive reviews | 0.0% of reviews | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 27 months | **Every 2 weeks** |
| Monetization | Paid | **Freemium** |
| Size | 3 MB | 25 MB |
| Requires iOS | **14.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Ville Kangas](https://appshunter.io/developer/1477308478) | [Nicola Eusebi](https://appshunter.io/developer/737311863) |

## What reviewers say

### Worry Monster

[App page](https://appshunter.io/ios/app/worry-monster/id1557717144)

This app helps users manage worries and anxieties by providing a digital space to write down troubles. Once written, the app metaphorically 'eats' these worries, offering a sense of relief. All entered text is securely destroyed, with no data collection.

**Highlights:** Write down worries, Digital worry eating, Secure data destruction, No data collection, Mindfulness tool

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### REM Sleep Tracker

[App page](https://appshunter.io/ios/app/rem-sleep-tracker/id6446677275)

This app analyzes Apple Watch sensor data to provide a sleep quality score. It offers detailed insights into sleep stages, heart rate, and weekly trends, helping users understand and improve their rest habits.

**Highlights:** Sleep quality scoring, Detailed sleep stage analysis (light, deep, REM), Heart rate monitoring, Weekly trend tracking, Sleep bank concept for habit analysis, Apple Health integration

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Sleep Score Premium Yearly | $9.99 | per year |
| Sleep Score Premium Yearly | $29.99 | per year |


## Frequently asked questions

### Is Worry Monster free?

Worry Monster costs $0.99, with no in-app purchases.

### Is REM Sleep Tracker free?

REM Sleep Tracker is free to download, with in-app purchases available.

### Do Worry Monster or REM Sleep Tracker have ads?

Neither Worry Monster nor REM Sleep Tracker shows ads.

### Which is updated more often, Worry Monster or REM Sleep Tracker?

Worry Monster ships an update every 27 months, and REM Sleep Tracker every 2 weeks. Most recently, Worry Monster was updated on October 24, 2026 and REM Sleep Tracker on October 24, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*