Headphone Jacks: Any time moving parts are introduced to a device, it can increase the failure rate. Headphone jacks may not be motorized, but they see a lot of action from headphones and stress can frequently be placed on the contact points if you it while working out or other heavy activity.
Once your device is opened, headphone jacks are relatively easy and cheap to replace, but this assumes you can get in. Devices with unibody designs like the HTC One are difficult to enter no matter what task you're trying to accomplish. Headphone jack units are usually self contained and plug directly into the motherboard, though they are sometimes attached to the speaker assembly. You can check out one of the guides below to see how easy it will be for your device.