How do properly maintain an SSD not powered on frequently

I know SSD's are not meant for data backup, but I do have an external SSD drive that I only plug and use occasionally. I know from research that the data should still be fine at least a year, so I should plug it in no less than that. But... apart from plugging it in, do I need to do anything or will the controller just magically refresh everything? In that case: how long does it need to be powered for this to be completed? Some say you need to actually read through all data, or even re-write it all, however that would be possible on a system drive.

What gives? It's really hard finding some solid advice googling the matter.