Unfortunately recent testing ahs shown that SSDs left on the shelf experience data corruption after a while, so they need powering up and refreshing, which is a pain.
http://www.anandtech.com/show/9248/the-truth-about-ssd-data-retention
http://www.extremetech.com/computing/205382-ssds-can-lose-data-in-as-little-as-7-days-without-power