Personally, I keep the redundant backup as cold storage to minimize loss. Three 8TB content or archival drives that are always attached via USB but not powered until needed, plus another on NAS for streaming, and two more 8TB each for double backup that are only turned on when I want to do a sync. So the drives get minimal wear, and whenever a primary dies, the backups get promoted and a new one is bought to be third in line. I have lost too much data in the past. As well as I can manage, never ever again.