Solid state drives may seem to be the best solution for storage, they are faster, more reliable and last longer. But they do not last forever, with a standard SSD lasting around four years. This means important data should not be kept on the same drive forever as one day it may be lost. A common solution for this is to backup everything on servers and other drives.
But why do solid states drives fail after a certain time, even though they do not contain any moving parts? All data is transported and stored with electricity, which is flowing electrons. Overtime as these electrons move in and out of the solid state drive, some get stuck and don't move, as if they are dead electrons. More and more of these 'dead' electrons get built up inside the solid state drive and lower the voltage. This can also impact performance of the drive, but when too many electrons get stuck in the drive, the voltage eventually gets too low to operate and any data is then inaccessible.