Risk of irreversible Jailbreaking is a complex process if you are not tech savvy. It is possible that you can "brick" your iPhone, a process that makes the iPhone useless. When an iPhone is bricked you need to run a complete restoration on it with iTunes. This refill the Apple bootloader and removes jailbroken settings. There is a small chance that you can damage your iPhone repaired; In this situation, you end up with an expensive paperweight.