If you start learning from the feedback you obtain through interviews or metrics, it is very likely that the flow or structure of your app will change. As business requirements change often, ad hoc changes need to be made. This requires you to refactor the code of your app. That is something that most developers consider to be important, but in reality it can be easily forgotten or it is never done, simply because there is not enough time for it. Sometimes, refactoring is considered to make the app unstable. However, do not let your technical debt become too large.

Technical debt or even spaghetti code can be the result if you understand underlying process insufficiently, or when you do not allocate enough time for development. In case a startup company has only business-oriented skills, it may have outsourced the development or it may have hired...