An untethered jailbreak means users can install it on their device once and for all. They don’t have to worry about a dead battery or restart requiring them to hook up to a computer and jailbreak the device again.

via Untethered iOS 6.1 evasi0n jailbreak arrives for iPhone, iPad, and iPod touch devices – The Next Web.

If you ever need to do this this article would be a good place to start your journey.