Nokia Windows Phone: Question 7

We’re running a challenge where in you can Win a Nokia Windows Phone. The rules of said competition are detailed in the aforelinked post. There will be many more questions over the coming weeks, here is question 7.

Question 7

Rather than just talking about, and documenting, the design language for Windows Phone, Microsoft decided to provide a set of default styles, font sizes and other resources that developers can reuse within their applications.

List a resource that is available to all Windows Phone developers and give an example of where you should (and for a bonus entry, where you should not) use that resource?