The best thing to do if you plan on storing locally is to use a RAID ("Redundant Array of Inexpensive Disks"). This uses software to share data across multiple drives, with some of the drives' capacity being used for redundancy. So you might have a six-drive array, and if one of them fails you can still recover all of your data and just swap in a new drive. There are a number of manufacturers who make pre-made boxes for these that you can plug into your network and set up with a pretty user-friendly interface. One thing you do lose is a little bit of total storage capacity, but large drives are quite inexpensive these days compared to redundancy. Exactly how much you'll lose depends on what RAID setup you're using (there are a number of kinds) but for example you could have a setup using 4x 10TB drives that could handle total failure of one drive and end up with 30TB of usable space.