Up to what level should user stories be broken down?

I want to know up to what level should user stories be ideally broken down? Suppose I have a story that says: "Test XYZ v3.0.0" Here XYZ refers to the application to be tested. If I write down the story using the normal format, it would say: "As an XYZC user, I can have the bugs removed and enhancements made, so that it can be very useful to end users." I feel if the story is written down in this manner, it would be too generalised and big for development purposes. If I further break it down into two parts i.e. two stories, they would look like: "As an XYZC user, I can have the bugs removed, so I can control technical debt." and... "As an XYZC user, I can incorporate the enhancements, so end users can enjoy enhanced user experience and get more out of the application" I could go on breaking down the stories into even more parts to make them more meaningful and effective. However, I would like to know up to what extent should stories be ideally broken down to be effective from the development point of view?

Posted By - Jhon