Bad Power Supplies

I just had a month old 550w power supply die on me, and it replaced a 350w power supply that died.  I now have a 420w power supply, but should I be concerned?  What is it causing my power supplies to fail?

>>3

Not at all, in fact, my computer is setup in a room with only one computer desk.  I also have my PC hooked up to a UPS AND a surge protector.  I just don't understand what is causing the faulty power supplies.  This last one that died (the 550w ps) made a really strange smell.  I could notice it too.  So maybe it was just defective.