SSD Sleep or Shut Down? I have a MacBook Pro with SSD drive.  I am concerned that leaving it on (closing the lid when not in use) will wear out the SSD drive quicker than fully shutting the system off.  The boot up time is really not too big of a deal considering that when I'm away from the computer it's usually for many hours at a time. The way it is right now the unit is up instantly when I turn on the power button.

Which mode will best prolong the life of the SSD drive?
Unless you do some serious data crunching with your Mac, you shouldn't need to worry about SSD wear. It does happen, but any relatively recent SSD does a lot to combat it, both by minimizing write amplification, and by setting aside spare area to do wear levelling and compensate for bad flash.

If you're really worried about it, you can still sleep, but not use hibernate mode, meaning that nothing gets written to disk. Just open Terminal and run sudo pmset hibernatemode 0. You can then delete the sleep file to free up some space: sudo rm -rf /var/vm/sleepimage.