I recently came across a few discussions from people who is confused what TARIF can do for them.
As part of the job catalog process, you must identify all of the associated pay structures that will be linked to the job through infotype 1005. A little known feature called TARIF will assist you in the process and allow you to have multiple infotype 1005 on the same job, thus making job object more general and globally used.
I've written up a document explaining the process further. Click HERE for it.
You could find other documents I've written @ http://www.saphelpbykevin.com