I have a 22TB RAID10 system out in my detached garage that works as an "off-site" backup server for all my other systems. It stays off most of the time. It's on when I'm backing up data to it, or if it's running backups to LTO tape. Or it's on when I'm out in the garage doing whatever project, I use it to play music and look up stuff on the web. Otherwise it's off, most of the time.