Currently using SharePoint as a document management system (replaced our drives) and one of the benefits was to utilise retention to avoid hoarding documents going back 20 years!
So it would be great to hear how you have applied it and experiences with it:
do your organisations staff have to manually tag the document or have you automated the retention label based on content type?
do you have just the standard - after x years delete. Or do you have a review, i.e. untouched documents after 18 months will be pinged to the owner to confirm whether it should remain (and then stay for the remaining retention period) or whether it's no longer needed and can be deleted?