Hey guys. I have a 13 inch 2012 MacBook Air. I have gotten my fair share of mobile use out of the thing, but I'd like to ask other owners of my particular type of machine how their stock battery is holding up as of Jan 2015? Just 3 days ago I noticed the "Service Battery" warning under the battery menu and thought that it was a bit odd to see. It didn't surprise me in the least considering the machine's age and charge cycles, but what its been doing after this is actually surprising me. I know that Lithium Ion cells don't last forever, but mine just decided to apparently take a nose dive off a cliff in less than one week. A week ago, I was able to get several hours per charge. After this problem cropped up I downloaded an app, I believe it is called "Battery Health" to check the vitals, and it did confirm that the battery is of course wearing out slowly. The max mAh was much lower than the projected factory mAh for the battery and it was showing 77% health. So I decided to drain the battery by running a full screen youtube video and it killed it in 30 mins. I plugged her in, let her regain a full charge (my suspicion was maybe it needed a good full drain cycle) and low and behold, now were hovering at 64% health and dipping into the 4000's mAh (was 5159 before). The calculated remaining time is all over the place too, i've watched it jump between every single number between 20 minutes and 3 hours and not 10 mins off the charger i'm down to 88% from 100%. I know I have to replace, but do these batteries usually have such a steep curve when it comes to dying? I thought it would be gradual. Maybe it's gone totally bad with intermittent problems?