A couple of days ago, we finally tracked down an elusive bug that was eating up storage resources for more than a year.
This will pave the way for us being able to turn "Monthly 'Rolling' Refresh" back on.
We are in the process of deleting more than 22 million images that were "orphaned", so that will take awhile. During this time, the service response will slow, but it will not be noticeable to end-users. The purge has been in process for 2 days already, and it has slowed typical delivery response times from 0.001s average to about 0.02s, which is considerable, percentage-wise; but negligible in the grand scheme of things.