Hello, I would like to ask about the battery life of your MacBook Pro Retina 13" late 2013. I have a second-hand laptop, while used, 6 cycles the battery, and also give me a little battery will last. If I'm at full brightness, surf the net, listen to songs, my macbook will last 4-5 hours, is this normal? Apple still gives time 9 hours. When I got almost to the minimum brightness lasts only seven hours, but even so it is a little mean. How long the battery will last you at what load?