Clearly, it’s harder to rectify issues as a product approaches the end of its development life cycle. The earlier bugs are introduced (e.g., during the design phase), the higher their potential impact, and the more complex they can be to resolve. The changes made for a bug fix can also affect the application’s functionality. In turn, developers may need to make further changes to the codebase, adding to the cost, time, and effort. So it’s important to find and fix bugs during the early stages of development.
Consider an example of a bank finding a security flaw after releasing an application used by thousands of customers. If the bank had found the issue earlier in development, there would have been some cost to fix it. But now, the bank will spend exponentially more effort, time, and money to fix it. Additionally, the complexity of implementing changes in a live production environment further increases the overall cost associated with late-stage maintenance.