I can't get myself to care. I've written two novels, and hundreds of thousands of words of articles and internal documents, and I can't for the life of me remember the rules for this, and neither can most other people. For my novels, my editor fixed it, because there are the odd pedant that cares and leave negative reviews of these things are not "right". For everything else I just use hyphens. It does not matter - it is clear from context.