# 66 Challenge vs Go Gray | Reduce Screen Time

The clearest difference is update cadence: Go Gray | Reduce Screen Time at every 2 days against 66 Challenge's every 5 days. 66 Challenge's advantage is device support (3 vs 1) and iOS requirement (13.0 vs 16.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. 66 Challenge sells 3 in-app purchases, starting at $3.99 per month and Go Gray | Reduce Screen Time sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

66 Challenge ships an update every 5 days, Go Gray | Reduce Screen Time every 2 days. Both last shipped on October 31, 2026.

## The numbers

| Metric | 66 Challenge | Go Gray | Reduce Screen Time |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (5 ratings)](https://appshunter.io/ios/app/66-challenge/id6758270405/reviews)** | — |
| Number of ratings | **5** | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 5 days | **Every 2 days** |
| Monetization | Freemium | — |
| Size | 18 MB | 18 MB |
| Requires iOS | **13.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 12+ | 4+ |
| Developer | [Moad Ghajjate El Fal](https://appshunter.io/developer/1871890791) | [atareh studios inc](https://appshunter.io/developer/1887940603) |

## What reviewers say

### 66 Challenge

[App page](https://appshunter.io/ios/app/66-challenge/id6758270405)

Build lasting habits with a science-backed system designed to guide you through a 66-day journey. Track daily progress, visualize your transformation, and stay motivated with social features and achievements. Transform your life one habit at a time.

**Highlights:** Daily habit tracking, Progress visualization, Streak protection, Social feed and squads, Customizable reminders, Achievement badges

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $3.99 | per month |
| Pro Annual | $29.99 | per year |
| Pro Lifetime | $59.99 | one-time |


### Go Gray | Reduce Screen Time

[App page](https://appshunter.io/ios/app/go-gray-reduce-screen-time/id6761135943)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Go Gray Pro Monthly | $2.99 | per month |
| Go Gray Pro Yearly | $24.99 | per year |


## Frequently asked questions

### Is 66 Challenge free?

66 Challenge is free to download, with in-app purchases available.

### Is Go Gray | Reduce Screen Time free?

Go Gray | Reduce Screen Time is free to download, with in-app purchases available.

### Do 66 Challenge or Go Gray | Reduce Screen Time have ads?

Neither 66 Challenge nor Go Gray | Reduce Screen Time shows ads.

### Which is updated more often, 66 Challenge or Go Gray | Reduce Screen Time?

66 Challenge ships an update every 5 days, and Go Gray | Reduce Screen Time every 2 days. Most recently, 66 Challenge was updated on October 31, 2026 and Go Gray | Reduce Screen Time on October 31, 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.*