When my iPod touch microphone broke, I had to make a genius bar appointment. I went in the store (surprisingly not so busy the day after the 5S came out) and a genius helped me out. First he went in the back and cleaned it. I tested it and there was still the same problem. Then he reset all settings and it seemed like the problem might be gone, because you could hear talking after recording, but it was quiet. I assumed it was hard to hear only because of all of the noise around me but once I left the store it was still barely audible. I went back in, told them that the issue was still there and they said I needed a replacement.
My device was a year old, and now I have a brand new one with a new battery that actually held a charge. On top of all of that, I got all of the apple apps for free because I guess this counts as a new device, and when I checked my applecare, it had been extended to SEPTEMBER NEXT YEAR! I guess it was a good thing I caught that the problem was still there before going home because if I hadn't, the next time I would have been able to go was after my applecare would have expired.
I went home, plugged it into my mac, and restored iOS 7 onto it (it came with iOS 6 and I know many of you will say I should have kept it, but I actually like the new features and design of iOS 7). When I restored my iCloud backup and synced my music, it was exactly how I liked it and had it before, even the website I had opened when I made my backup.
The only issue with this device is that the lock button only works if I press on the right side of it (as in not left). I don't think it is worth another trip to the apple store and having to get another replacement device, and I only had two screen protectors, both of which I used (I like keeping my devices in mint condition).