Change Folder Label if new content added.

I would like to give an indicator if any new content is added to a folder. Specifically, if I add a receipt to a reimbursement folder, I want it to have a label color added so the bookkeeper knows to look in it.
Any ideas on how to make this work?
On top of that, then, is there a way to remove the label through some means? Perhaps by all the content being removed, or "If folder is empty, remove label"
Thanks in advance.
Josh
Any ideas on how to make this work?
On top of that, then, is there a way to remove the label through some means? Perhaps by all the content being removed, or "If folder is empty, remove label"
Thanks in advance.
Josh