When it comes to my photos & family documents, I go by the rule; 1 is none, 2 is one & 3 is a backup.
I stred with photos over 25 years ago,,, it got a lot easier when I discovered software on a Kodak printer that would recognize photos individually, laid out on a scanner.
Which is why I have 3 internal HDs, one 64G USB3 stick and a TB external HD.