Quarterly CPU patching Process

I would like to know how other organizations react and handle when the Oracle critical patches are announced.  Do you research what problems these patches are fixing and determine if to apply or do you just apply them no matter what?  After you apply them, how much of the application do you test afterwards?  The April critical patch documentation is so generic we would not know what to test in the application before deploying to Production. 

If we applied every quarter and tested and deployed, it is all we would get done.

Thanks