"Overvolting kills your CPU" is a concern, but it's important to remember that a lot of these overclocking forums and resources get a lot into the theoretical and put blinders in the practical.
Yes, pumping more voltage through the chip will reduce its lifespan. Yes, theres a fancy curve and some math that will estimate theoretically by how much under perfect circumstances if its run 24/7/356. Some of those results are big and scary, but need to be taken into context. If a .02v overvolt will reduce the life of your chip by 25%, and that lifespan was say, 20 years (note that these numbers are all made up), the overvolt is knocking five years off the life of the chip, but it'll still last for another 15 years.
As long as your not overvolting to the point of instantly frying the chip, odds are you're going to replace the whole system anyway before the chip itself dies because of the increased stress. There's plenty of cases just on this forum of people with highly overclocked chips of all shapes and sizes eventually hitting a little instability after *years* of use and having to lower the overclock a little to keep stable, but they still work just fine.