This brief guide will give you some important tips to help alleviate any confusion you might have when using gfxCardStatus.
Far fewer apps will cause the more power-hungry graphics to turn on if you're using OS X Mountain Lion (10.8). If you have not yet upgraded to Mountain Lion, please consider doing so.
Even if you haven't upgraded to Mountain Lion, I recommend staying on Dynamic Switching as much as possible. Don't switch modes unless you absolutely need to. See switching for more details.
Certain apps like Parallels and VMware Fusion have good reasons for turning on the more power-hungry graphics. Other apps, like Google Chrome and Skype, do not.
Google Chrome has had on-and-off issues with graphics switching that still crop up pretty frequently. Safari is more stable and graphics switching-friendly. I strongly recommend using Safari instead of Google Chrome for optimal battery life and user experience.
You cannot use external displays (including projectors) while using gfxCardStatus in Integrated Only mode. To use a display, stay on Dynamic Switching.