I am a solo builder and one thing that helped me a lot was this: most of what looks like a "necessary abstraction" is actually scope creep with a different name. I was adding a flag for every new feature and I noticed the pattern in my own code, so I made one rule: a feature can not land until its flag-off behavior has a test. That changed how I see flags. The flag is part of the product, not an escape hatch. Three features in my backlog died by themselves when I started thinking like this.