# LifeOS vs Second Brain

The clearest difference is update cadence: LifeOS at every 8 days against Second Brain's every 3 months. Second Brain's advantage is iOS requirement (15.0 vs 26.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. LifeOS sells 2 in-app purchases, starting at $2.99 per month and Second Brain sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

LifeOS ships an update every 8 days, Second Brain every 3 months. The most recent releases landed on September 23, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | LifeOS | Second Brain |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 8 days** | Every 3 months |
| Size | 14 MB | 25 MB |
| Requires iOS | 26.1 | **15.0** |
| Devices | **iPhone, iPad, Mac, Apple Watch** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ryota Kimura](https://appshunter.io/developer/1832418496) | [Selahattin Bozat](https://appshunter.io/developer/1895293163) |

## What reviewers say

### LifeOS

[App page](https://appshunter.io/ios/app/lifeos-self-observatory/id6755999327)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| LifeOS Pro (Monthly) | $2.99 | per month |
| LifeOS Pro (Yearly) | $29.99 | per year |


### Second Brain

[App page](https://appshunter.io/ios/app/second-brain-notes-and-knowledge/id6775839727)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Second Brain Premium | $9.99 | one-time |


## Frequently asked questions

### Is LifeOS free?

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

### Is Second Brain free?

Second Brain is free to download, with in-app purchases available.

### Do LifeOS or Second Brain have ads?

Neither LifeOS nor Second Brain shows ads.

### Which is updated more often, LifeOS or Second Brain?

LifeOS ships an update every 8 days, and Second Brain every 3 months. Most recently, LifeOS was updated on September 23, 2026 and Second Brain on September 24, 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.*