Solid-state memory? What does Wikipedia have to say about this? Oh, interesting. So the most interesting point in hand is the positioning on archival use of solid-state memory. First of all, we do know from first-hand experience from BIOS firmware that solid-state memory does last quite a long time, even without refreshes. However, according to Wikipedia, for larger capacities of solid-state memory, errors can occur after only 1-2 years in storage. Solid-state memory retention is more reliable when powered on and wear-leveling is continously operating. Also, solid-state drives tend to have the same failure rates based off of age, more so than the intensity of use. The article on longevity is from the year 2015.
20180828/https://en.wikipedia.org/wiki/Solid-state_drive
20180828/https://www.anandtech.com/show/9248/the-truth-about-ssd-data-retention