By understanding it. Complexity will manifest if the software is complex enough, but where? You can have code that's easy to read and complicated to change. Or

By understanding it. Complexity will manifest if the software is complex enough, but where? You can have code that's easy to read and complicated to change. Or you can have code that's complicated to read and understand but easier to change. Perhaps it's easy to read, and change but complicated to scale? I like to shove the complexity into areas I don't care about. If I'm building a system that doesn't need scale, I'll take readability and easy to update over scalability. It's a balancing act.