# Residue Disorders vs Kid Study

The clearest difference is price: Kid Study at Free against Residue Disorders's $4.99. Kid Study also leads on update cadence (monthly vs every 42 months). Residue Disorders's advantage is in-app purchases (none vs 5) and iOS requirement (11.0 vs 15.5). On ads and device support there is nothing between them.

Kid Study is free to download; Residue Disorders costs $4.99 up front. Kid Study sells 5 one-off in-app purchases. Residue Disorders asks for nothing beyond the download.

Residue Disorders ships an update every 42 months, Kid Study monthly. The most recent releases landed on October 8, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Residue Disorders | Kid Study |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 42 months | **Monthly** |
| Size | 46 MB | 24 MB |
| Requires iOS | **11.0** | 15.5 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Blue Tree Publishing, Inc.](https://appshunter.io/developer/496143325) | [Jen Hsien Chen](https://appshunter.io/developer/1576491016) |

## What reviewers say

### Residue Disorders

[App page](https://appshunter.io/ios/app/residue-disorders/id615941080)

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

**In-app purchases:** none


### Kid Study

[App page](https://appshunter.io/ios/app/kid-study/id1613678208)

**Features:** macOS Compatibility

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Animal Full Version | $0.99 | one-time |
| Food Full Version | $0.99 | one-time |
| Items Full Version | $0.99 | one-time |
| World, Environment & Nature Full | $0.99 | one-time |
| Full Version | $2.99 | one-time |


## Frequently asked questions

### Is Residue Disorders free?

Residue Disorders costs $4.99, with no in-app purchases.

### Is Kid Study free?

Kid Study is free to download, with in-app purchases available.

### Do Residue Disorders or Kid Study have ads?

Neither Residue Disorders nor Kid Study shows ads.

### Which is updated more often, Residue Disorders or Kid Study?

Residue Disorders ships an update every 42 months, and Kid Study monthly. Most recently, Residue Disorders was updated on October 8, 2026 and Kid Study on October 25, 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.*