Hi, I'm an extremely heavy user of my MBA 2013 13". I've recently run into a problem with the keyboard. I type almost 12 hours a day, for work and programming. I am also a writer on the side. I'm a touch typist, meaning I type without looking at the keys amongst other things. Anyhow, my enter key has become rather unreliable. I do not eat or drink by my MBA, I do not do anything that would cause dust to get underneath the keys (except perhaps running a fan by my desk). However, if I do not press the enter key hard enough, or if I press the wrong "part" of the key (corners) it will not send it through. This would not be such a huge issue; I could just press it harder, but this is a hindrance since I type so much. Any advice? Is there any service that I could do to fix this issue. My MBA is still under warranty, but the Apple store is 45-60 minutes away. Thanks.