"Things that do not belong in your package should not be in your package."
This seems pretty obvious, but it is easy to look at a package and tell yourself that leaving that particular item in will not hurt anything. Before you leave it in there, consider the problems it may cause you down the road:
- if the item should be set as the keyfile for a component, it may cause the application to reinstall itself if it is deleted.
- if the file or registry entry should be changed or updated, a reinstallation of the package will result in a needless conflict that will reset the change or update.
For a host of other reasons and a tool to help you identify what does not belong in your package, check out PackageCleaner.