Its not neccessary, its just I had a few parts go in a short amount of time, was literally one after the other. I wouldn't like to have to go through another country for returns, and would hate to go thrugh ebay, but its up to you where you get it from, you are more likley to not have a single problem. eVGA is a good manufacturer and have very few returns. Unlike XFX.
Cheap PSU's are not reliable, don't supply enough amps on the 12v for high end systems, and have early deaths, and when they do, they will likley take out hardware, it is not worth it.