I use yum on pretty much a daily basis, and I've added a small collection of repos (repository). I use livna and FreshRPMs for instance. Now, for some reason these two repositories overlap, meaning, if I run yum update, livna will try to upgrade my freshrpm packages. Up until now, I've managed around this by using --enablerepo and --disablerepo. However, there's a much better way, I installed a yum plugin called yum-priorities.

Using yum (obviously), I simply installed this on my Fedora Core box with

# yum install yum-priorities

With this plugin installed, all I have to do is to give the FreshRPMs repo a higher priority (lower priority value) than the livna repo (default priority is 99). For example:

[freshrpms]
name=Fedora Core $releasever - $basearch - Freshrpms
priority=80
.
.
.

Now when I run yum update I get a message like

...
Loading "priorities" plugin
Setting up Update Process
Setting up repositories
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository protections
96 packages excluded due to repository priority protections
No Packages marked for Update/Obsoletion