Android keystores: Debug/Release key for each app?

Question

I'm getting ready to release an app on the android market and going through the docs for creating debug/release keys. Am I supposed to have a Debug/Release key for each application, or just a general Debug and Release key to use for all applications?

"...You use debug mode when you are developing and testing your application. You use release mode when you want to build a release version of your application that you can distribute directly to users or publish..."

Answer 1

"In general, the recommended strategy for all developers is to sign all of your applications with the same certificate, throughout the expected lifespan of your applications" - Signing Your Applications

The link also lists some of the reasons why it's better to use a single key for all your applications.

Answer 2

you don't have to create more than one release keystore to sign your app... only one is sufficient even more, if you intent to release an update to your app. , it must be signed withe the same keystore.