Although you wouldn't think that repairing the power button is something you imagined you would ever need to do, sometimes it's needed. Some iPhone models have known issues with power buttons that suddenly stop functioning. Or, you may drop your phone on the power button, causing damage to it. You can still use the phone without repairing that, but it's extremely annoying not being able to shut your screen off when you want to.
Believe it or not, repairing a power button is not that big of a deal. We stock power button assemblies for all models of iPhones, and the repair can typically be completed within an hour.