Yes exactly. The thing I learned is that it all has to work independently, then you glue it together with policies. Even the simplest hard coded decision is goi

Yes exactly. The thing I learned is that it all has to work independently, then you glue it together with policies. Even the simplest hard coded decision is going to be wrong in some context. Even with such an approach, you’ll still miss something, but at least policy mechanisms provide a pattern for refactoring and new features. I ended up building what we might call a declarative billing platform. You tell it what you want, and it tries to make it happen. Very successful, technically, but sadly I left the industry before it got into serious production.