I got my 13" retina MBP a few weeks ago, and used it quite a lot since then. However I noticed that battery drains incredibly quickly, I'm asked to recharge it after 2 1/2 hours of usage.
I'm using it for programming, and I have a lot of stuff running in the background (nothing takes a lot of CPU except Chrome; just playing music, mail, some chat programs). Is that why the battery drains so quickly?
The system report says that the battery is in good condition. According to the activity monitor the process "Google Chrome Renderer" needs ~100% CPU. I have no clue why it needs that much, can that be a reason for the low battery life?
Edit: I did a bit of research about Chrome's CPU usage, and it looks like a lot other people had the same problem. I followed some advice that those people gave, and now Chrome is back to less than 1% CPU usage. :) I now have 5+hrs battery life when I'm using my MBP intensively. I even had 7 1/2 when I wasn't connected over Wi-Fi and the screen didn't use a lot of light.