Simplicity and fewer dependencies

Simplicity means choosing the solution with the fewest moving parts, dependencies and ideas that still solves the problem. A dependency is outside code your project relies on, such as a library or another service. Every line of code, library and service is something someone has to understand, update and debug, often long after you have moved on.

So removing things can be high-leverage work. Examples: deleting a feature nobody uses, replacing a large library with twenty lines of your own code, or removing a cache nobody needed. Senior engineers are judged partly on what their systems cost to run and change. Before adding anything, ask: "What is the simplest thing that fully works?"