If you buy fresh SSD/NAND media, treat it as write-once (or write to it just a few times) and fill up only a small-enough fraction of the logical space (so that the device can use pseudo-SLC "fast/caching" mode for the entirety of your data) the data on it ought to last a really long time. Especially if you avoid high temperatures during storage, and read it back every few years. Physical data remanence is much more of a concern for NAND that is nearly worn out.