I've had this (refurb) mid 2014 15" rMBP (NVIDIA 750m) for a five days now. From unplugging, I'm seeing 4 hours battery time. I was expecting up to 8 hours as advertised (6 to be realistic). I was seeing 3 hours from a 5 year old MacBook Air. (Example: Unplugged an hour ago and it says 3:17 remaining. All I'm using is Safari, iTunes, and Airplaying the music to Apple TV). I already use Safari only and keep brightness 2/3rd the way. I doubt the 750m GPU is kicking in during web and music. Is this normal for you guys? What expectations should I have? What are some best practices to maximize battery? Plug-ins, software, settings? Thanks.