Which four?

I think I get the picture about repositories: only four. But I notice that, for example, there’s an OpenSUSE 11.1 update repository and a Main Update repository. Which one should I keep; or does “updates” mean both? Similarly, there’s a distro and main for oss and non-oss, also. Is it one or the other or both, respectively?

Nevermind; I see the answer in: Repositories/11.0 - openSUSE-Community.