- 2009-02-10, 0.01: first shot --Lkundrak 20:57, 10 February 2009 (UTC)
No guideline that would limit the use of Epochs exists.
Following change to Packaging Guidelines is proposed: Add a section Use of Epochs which would read:
Use of Epochs
The Epoch tag in RPM is to be used only as a last resort, and should be avoided whenever possible. However, it is sometimes necessary to use an Epoch to handle upstream versioning changes or to ease transition from third party repositories.
Epochs from Third Party Repositories
If a package to be imported is or previously was present in a publicly accessible repository, the packager can optionally include an Epoch tag equal to that of the most recent version of the third-party package.
Use of Epochs has been controversial and has been source of number of (sometimes unnecessarily harsh) disputes.  It generates unnecessary mailing list traffic so is better cleaned up :)
This guideline is consistent with existing packages, and since it is only relevant to new packages to be imported it doesn't involve any changes to already imported packages.
See Talk:PackagingDrafts/Epoch for discussion.