Stamina on my 2013 11" i5/8/256 has been much better than expected. If I really monitor my app usage and keep the screen brightness down to 75% or lower, its seems no trouble to squeeze 10 to 12 hours indicated of battery life out of it. While I rarely have the need to go more than 8 hours without access to a power outlet its great to have the reserve. In fact, typically its 4 to 5 hours where I've been in meetings, on the airplane, or at a convention. However, when only looking at these kind of timeframes, I was constantly worried that I might need some extra time to finish up some work or answer some last minute business request. With the knowledge that I could go well beyond my typical 4 to 5 hour stretch, I'm no longer worried about power management or looking around the room for a vacant power outlet. Its really a liberating feeling that the extra capacity is there, even though you might not need it. It makes the mobile experience so much better!