A common question when it comes to migrating APEX applications is "can I just export a page".
There are more technical posts on the topic of exporting APEX applications than this one out there, eg:
I just wanted to clarify the concept, perhaps for those learning the tool.
So the answer? Sure you can, but what about other components related to that page? A breadcrumb; menu list entry; LOV? What about application items? Are you sure you've got everything?
So with this in mind, when you start the process export an APEX application you have a side-option to do a Component Export, which might look like this:
From here we can not just nominate the page, but identify other components to add to the export. The exported SQL is just a subset of the entire application. (I wonder when this will become JSON?)
However, the only time I consider doing this is for a reporting application where I know the only components in a new report is the page itself and a breadcrumb. The menu is dynamic so the existence of the page is enough.
Otherwise, perhaps for an operational style application, I think the risk of missing changes it too high not to do a full export.
Build options can also help you find your bundle, but even then diligence needs to be high.