Even the most reliable digital storage device will eventually fail — while hard drives are expected to last 3-5 years on average, some will fail much sooner. Several others continue to function for more than a decade, but their mechanical components eventually fail. Solid-state drives and other devices have lifespans that are comparable to one another.
Backups of your important files are the only way to ensure that you do not lose any data. We recommend that you keep at least two backups, one of which should be stored offsite (cloud backup services are an excellent option for consumers). In order to ensure that your backups are complete and usable, you should check them on a regular basis.