# Smart Solar vs Useful Lock Screen Memo

The clearest difference is in-app purchases: Smart Solar at none against Useful Lock Screen Memo's 1. Smart Solar also leads on ads (none vs shown) and iOS requirement (12.0 vs 26.0). Useful Lock Screen Memo's advantage is update cadence (weekly vs every 2 months). On price and device support there is nothing between them.

Both are free to download. Useful Lock Screen Memo sells 1 one-off in-app purchase. Smart Solar asks for nothing beyond the download.

Smart Solar ships an update every 2 months, Useful Lock Screen Memo weekly. The most recent releases landed on September 19, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | Smart Solar | Useful Lock Screen Memo |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Weekly** |
| Size | 108 MB | 118 MB |
| Requires iOS | **12.0** | 26.0 |
| Devices | iPad | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Intelade Inc.](https://appshunter.io/developer/590626449) | [katapu.net](https://appshunter.io/developer/381898924) |

## What reviewers say

### Smart Solar

[App page](https://appshunter.io/ios/app/smart-solar/id6443642795)

**Features:** macOS Compatibility

**In-app purchases:** none


### Useful Lock Screen Memo

[App page](https://appshunter.io/ios/app/useful-lock-screen-memo/id6799839918)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $5.99 | one-time |


## Frequently asked questions

### Is Smart Solar free?

Smart Solar is free to download, with no in-app purchases.

### Is Useful Lock Screen Memo free?

Useful Lock Screen Memo is free to download, with in-app purchases available.

### Do Smart Solar or Useful Lock Screen Memo have ads?

Useful Lock Screen Memo shows ads; Smart Solar does not.

### Which is updated more often, Smart Solar or Useful Lock Screen Memo?

Smart Solar ships an update every 2 months, and Useful Lock Screen Memo weekly. Most recently, Smart Solar was updated on September 19, 2026 and Useful Lock Screen Memo on September 10, 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.*