If the glass/LCD is cracked, has a distorted image, no image, or is malfunctioning.
If the port is damaged or is unresponsive to the headphone jack.
If the button is jammed, missing, or is unresponsive.
If you hear fuzzy/cracking sounds, if sound fades in and out, or there is no sound at all.
Front / Rear Cameras
If the camera is cracked, not opening, or obscured.
Side Buttons / Mute
If the volume buttons are jammed, missing, or unresponsive & if the mute switch is sticking or jammed.
If your device is not charging, not holding a charge, or dying faster than it should.
If the button does not respond, is jammed, or is removed.
If you are unable to communicate in a call or if voice control isn’t working.
If you power down the device and it turns right back on or you are having trouble connecting the device to a computer or charger.
If you can’t hear your audio or use speaker phone.
Depending on the severity of the damage and what parts were affected.