Since any drive or such can fail without much notice or one of the more common issues come up (accidental delete) I don't see where you have your 2 copies of what you can't lose.
I have been told that a hard drive is most likely to crash within a few weeks of purchase.
I recently bought an external hard drive, and backed up all of my files to it. I plan to reformat my computer. How long should I wait before doing so?
I assume that the hard drive should not be sitting in the box while I wait. Is it enough to plug it into my computer, or should I regularly move files in and out of it?