yum package cleanup

[Mike Wright]

Hi all,

I would like to be able to save the rpm files that yum downloads.

Thanks to the following nugget from Google...

"I believe what you are looking for is /var/cache/yum/<repo>/packages. 
This directory is expunged during package cleanup."

...I now know where they are stored.

Two part question:

   When is package cleanup performed?

   Is there a way to prevent the expunging?

Thanks,
Mike Wright