When-ever I edit my sources file, I always make sure I have a mirror for stable, testing, non-us, and security.

Is this correct for a testing branch?

What I mean is, do I need to include the branch I'm on and the ones below it? or is every package that I could ever need available in say testing.


Regards,
Gavin

Mixing branches is not recommended. Testing uses a newer gcc compiler now, which will conflict with stable. But you may not have noticed this as apt will choose the latest versions by default, unles you told it to do otherwise with the preferences file.

Testing has all you'll ever need and gets software updates. Stable has all you'll ever need, but doesn't get updates anymore (except for security).

If you want packages from testing and unstable while running stable, I recommend to put APT pinning into effect so that one can do so in a controlled fashion - otherwise the system will invariably start taking packages from unstable as those are the latest versions and by default latest version gets highest priority. But with APT pinning one can still have the highest priority on stable yet still in many cases be able to install things from testing and unstable. Note though that sooner or later one will stumble upon things that cannot be installed unless a massive amount of packages will be upgraded to versions from testing or unstable. At that point one has to make a decision
A) Keep using the versions provided by stable
B) Effectively upgrade the system to testing or unstable
C) Attempt to find a backport of the package

Regarding APT pinning

• Apt-Pinning for Beginners - perhaps the most well-known of documents regarding this
• Apt-pinning - Using Packages from Testing and Unstable on Debian Stable - a document that I have myself written.

And regarding the non-US one, that doesn't exist anymore since the release of 'sarge'.