IDFA is not shared per app, only across developer accounts. Your Facebook and Snapchat apps don't see the same IDFA.
So I am irked I didn’t research before editing :-/
The APIs for this are very clear:
var advertisingIdentifier: UUID { get }
"Unlike the identifierForVendor property of the UIDevice, the same value is returned to all vendors. This identifier may change—for example, if the user erases the device—so you should not cache it."
The problem is periodic rolling of the ID doesn’t get you anything as any tracking service is simply going to track when the value changes in all the apps, and so all different IDFA tokens can always be tied to a single individual. Rolling, automatic or not, and irrespective of frequency gains you nothing. Tracking companies have repeatedly demonstrated a complete disregard for user privacy.
The /only/ way to fix this is to remove device centric ids from the platform. Then tracking frameworks can’t tied one user to multiple different app installs.
None of this “automatic rolling” nonsense - the API should not be there at all.