The Benefits of Private Methods

Private methods reduce the public surface area of classes. It also tells you what's safe to refactor in a way that doesn't affect outside clients. In ruby, everything is default public. People can use it by defaults with pack work. If you intentionally make this change tactically, but it's a really big change in terms of the mind set and so much more. A watcher as well as an observer will always be able to tell when something has been done correctly or not.