Hey @Josh108. Great question. For the most part, as long as you are attaching stylesheets, or JS via the app, nothing should be impacted by a filename change.
If you are attaching stylesheets through the app (i.e. editing head in the template) and then change the filename, it will not break.
Any JS files should also now be attached to the template using the tool rather than using the global footer technique, which means any filename changes will not break the page as well. And all files should scripts with <link> or <tag> as a way to pull in other files, those may not automatically update and we recommend using the in-app method.