Originally posted by automorphism No consumer-grade storage is long term. Even CD/DVD media degrades over time, although commercially-pressed ones do last a very long time. Don't expect anything -- hard drives, USB keys, XQD cards -- to last. Instead, create multiple backups, test them and replace them as soon as they fail. This includes at least one off-site backup such as cloud storage or a couple hard drives in an external location such as a safety deposit box or self storage.
There are anomalies like glass-etched storage designed to last longer, but those are impractical for consumer use.
In fact, in terms of degradation, the most durable storage medium is actually print. Print your best shots with quality printing and they will most surely outlast any digital storage medium.
Archaeologically speaking, cuneiform on clay tablets beats ink on paper!
An estimated 500,000 to 2 million clay tablets from between 2,000 to 5,000 years ago have been excavated. Only a very small number (about 3,000) scrolls of papyrus or parchment have survived the eons. Cellulose and leather are fragile polymers and tasty snacks for bacteria, fungi, critters, and flames.
Glass-etched storage looks both cool and brings the "memory crystal" concept of many a sci-fi story to real life.