I have a 2012 13' MBA with 350 battery charge cycles on the clock. I just checked my battery life on iStat pro and its showing 68% battery health. I was a bit shocked by this as battery health under Mavericks was always in the high 80%'s / low 90%'s ... Yosemite seems to have seriously affected how my battery life shows in iStat. I upgraded to Yosemite a few days after release, and I did not do a clean install. So I have a few questions: 1. Is 68% "normal" battery health for a 2012 MBA / 350 charge cycles? 2. Would an upgrade to Yosemite have affected battery health (or how it is showing in iStat) in any way? 3. If I did a full clean install of Mavericks would this make any difference to anything? 4. Is it worthwhile doing a full battery calibration and testing battery health again? Thanks in advance for any answers/comments.