So my nMp is now up and running and im using Lightroom and Photoshop more and more. My photo Libraries etc are Stored on a NAS drive and while the nMP has a 500GB SSD i would like to know if there would be any benefit in getting a external (Thunderbolt?) scratch disk. I dont fully understand SSD technology but would like to reduce wear and tear where possible to extend longevity. From a speed perspective i guess you cant beat an internal drive but i cant imagine a external thunderbolt drive would be noticeably slower. So, would an external drive be of benefit? If so does anyone have any recommendations? Also i have a couple of redundant 80GB WD 7200rpm drives lying around which could be used.