8 qualities of maintainable code

I just stumbled upon this tweet-shaped nugget of wisdom on Jason Gorman's Twitter feed and thought I'd share it.

8 qualities of maintainable code:

1. Can be (re-)tested quickly
2. Is easy to understand
3. Low duplication
4. Made of simple parts...
5. That do one job...
6. And barely know each other...
7. With swappable dependencies...
8. And client-specific interfaces

Read every point out loud, think about the code you're just working on, and let it sink in.