If you don’t know you have it…
then you don’t. (Not yet.)
Cleaning out the fridge after a power failure, I found three half-empty containers of anchovies. Because they magically migrate to the back of the fridge, every time I had needed some, I ended up opening a new jar, because the old ones were invisible. Not just invisible if I had looked for them, but so invisible that it never even occurred to me to look for them.
And this is even more likely to happen with the data on your hard drive. If you don’t know to look for it, if you don’t believe it’s there, it might as well be deleted.
And of course, this applies to our lost skills, confidence and experience as well.
It’s worth putting in regular effort to remind ourselves of what we’ve already got and how it has served us in the past.