The worst thing that can happen to your images is for your hard drive to fail and you not have backups, they all can be gone in an instant. External hard drives have gotten so cheap now that it’s very affordable to get one and copy all your images to it periodiacally. I try to back up once per month at least, though I will admit it is sometimes 3-4 months if I haven’t been very active.
There are many programs you can buy to make doing the backups easier, but my favorite one is free, and will copy just the changed and new images, so you’re not copying everything each time.
Sync Toy by Microsoft is what I use, small, simple and works great. You can get it HERE.