I didn't know that magnetic storage on HDDs was so fragile that it was necessary to make a new copy of the files every year.
A hard drive is a mechanical device with an electronic component. It has multiple drive heads skimming about platters spinning at 120 revolutions each second for a 7200RPM drive. Spinning those platters at that speed creates a significant rotational force, which causes vibration. Starting them up creates stress on the mechanical components, as does shutting them down. Applying and removing power creates wear on the electronic components. Like any other mechanical device, they will fail. And, like any electronic device, they will fail.
If you do not back up your data, it is not a matter of "if" you will loose your data, but "when" you will loose it.
The only way to truly safeguard the data stored on any storage medium is a regular backup regimen that is strictly followed, preferably with at least two copies (one copy of which is stored in another location for fire safety). I know people that maintain 4 or 5 different copies for really important stuff like photos or business documents. And, I wasn't being facetious in my earlier post by suggesting keeping it in a safety deposit box. I do that with my backup, and swap it out once a month (used to do it weekly, but since I retired I don't get to town that often anymore).
The best thing to do is sort your data into three piles: "I wouldn't care at all if I lost it", "Loosing it wouldn't kill me, but it would be time prohibitive to recreate", and "Stuff I would never, ever want to loose". Then, back up at minimum the last one, or the last two if financially feasible.