It's a good list, though like others, I think deletion is hard one.

I'm for renaming the objects for 13 months, give time for an end of year process to come, and then roll them off month by month after that. If no one's complained in that time period, it's likely not being used. Could it be? sure, but you can script the code, include it in a backup, or even leave it in a folder on the server. Not the world plan in trying to keep a clean system over time