3weeks Dev Log #1 — How a Single Talk Became an App

Something I Heard at a Talk

I don't remember exactly which talk it was. But I remember what was said.

"If you want to build a habit, just do it every day for three weeks. After 21 consecutive days, not doing it will feel strange."

The explanation was neuroscientific: repeating a new behavior strengthens the neural connections associated with it. 21 days is the minimum threshold.

The Problem: Tracking Whether You Actually Did It

After hearing this, I tried to put it into practice. I committed to exercising every day.

I fell apart within a few days. The problem wasn't willpower. Tracking whether I had done it each day was inconvenient.

I tried checking off a calendar — forgot. Tried logging in a notes app — scattered across multiple places, hard to review. Most importantly, I couldn't see at a glance how many consecutive days I was on.

"I Could Just Build an App"

I was an iOS developer. The obvious move was to build the tool I needed.

The idea was simple:

• Register a habit I want to build
• Get a notification at a set time every day
• Check off when I've done it
• Track 21 consecutive completions

Miss a single day and start over. That strictness was the point.

Loose rules don't form habits. The pressure of needing 21 consecutive days is what makes you show up every day.

Keep It Simple

When planning an app, you always want to add more features. Social features? Statistics? Sharing?

But this was an app I was building for myself. I put in only what I needed and pushed everything else to later.

• Add habit
• Notifications
• Daily check
• 21-day counter

Just that.

Summer 2019: Development Begins

It was a personal project with no real intention of putting it on the App Store.

Built with Swift and UIKit. Fast prototyping. I wasn't precious about the UI because this was a tool for me — it just had to work.

Then it got good enough that I didn't want to keep it to myself.

So I submitted it to the App Store.