Early on, in our first two years with NetSuite (2014-2015), our refreshes usually took a week at least, sometimes longer. Even worse, that was back when sandboxes refreshed in place (no separate activation step) so we’d be without a useable sandbox for a full week whenever we refreshed. They seem to go much faster for us now, and even then we usually don’t notice because we just activate the refresh after the email. But 48 hours is about average for us now.