It really does depend, any code, especially bad code, is very rarely bug free. So if you ever need to fix a bug the amount of time you will need to spend and revenue you might lose during the time might be worth the refactor beforehand In my experience, software or product development is never really "done" Customers, users and business will ask for new features and change of old features, external dependencies and used services will change, hardware will change Not being able to move fast enough, train new engineers and adjust to changing requirements will have a cost If I can't trust my codebase not to break on any new change it will be much much harder and more time consuming ie expensive to maintain it

This is not applicable to every piece of code and roi should always be kept in mind but I'm my experience it is almost always the case