# ReadiSync by Fatigue Science vs Clear Days

The clearest difference is in-app purchases: ReadiSync by Fatigue Science at none against Clear Days's 3. ReadiSync by Fatigue Science also leads on iOS requirement (15.0 vs 18.6). Clear Days's advantage is update cadence (every 2 weeks vs monthly). On price, ads and device support there is nothing between them.

Both are free to download. Clear Days sells 3 in-app purchases, starting at $1.99 per 7 days. ReadiSync by Fatigue Science asks for nothing beyond the download.

ReadiSync by Fatigue Science ships an update monthly, Clear Days every 2 weeks. The most recent releases landed on November 11, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | ReadiSync by Fatigue Science | Clear Days |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (7 ratings)](https://appshunter.io/ios/app/clear-days-quit-drinking/id6758869942/reviews)** |
| Number of ratings | — | **7** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Every 2 weeks** |
| Monetization | — | Freemium |
| Size | 66 MB | 10 MB |
| Requires iOS | **15.0** | 18.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, Apple Watch |
| Age rating | 4+ | 17+ |
| Developer | [Fatigue Science](https://appshunter.io/developer/1042111871) | [Cozy Paradise LLC](https://appshunter.io/developer/1857374376) |

## What reviewers say

### ReadiSync by Fatigue Science

[App page](https://appshunter.io/ios/app/readisync-by-fatigue-science/id1044418061)

**Features:** Vision Pro support

**In-app purchases:** none


### Clear Days

[App page](https://appshunter.io/ios/app/clear-days-quit-drinking/id6758869942)

This app helps you track your progress in reducing or quitting alcohol consumption without judgment. It focuses on celebrating your sober days and provides tools to manage cravings and support your journey.

**Highlights:** Sober day tracking, Progress visualization, Money saved calculation, Cravings support tools, Private by default, Journaling and insights (premium)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Clear Day Plus Weekly | $1.99 | per 7 days |
| Clear Day Annual | $29.99 | per year |
| Clear Day Plus Lifetime | $49.99 | one-time |


## Frequently asked questions

### Is ReadiSync by Fatigue Science free?

ReadiSync by Fatigue Science is free to download, with no in-app purchases.

### Is Clear Days free?

Clear Days is free to download, with in-app purchases available.

### Do ReadiSync by Fatigue Science or Clear Days have ads?

Neither ReadiSync by Fatigue Science nor Clear Days shows ads.

### Which is updated more often, ReadiSync by Fatigue Science or Clear Days?

ReadiSync by Fatigue Science ships an update monthly, and Clear Days every 2 weeks. Most recently, ReadiSync by Fatigue Science was updated on November 11, 2026 and Clear Days on November 5, 2026.

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