Polarizing filter, part 6

I purchased this Hoya circular polarizer a while ago.  I have used it a number of times to cut out the intense flares created on waters mainly and to bring up more details of the sky.  I did not quite think about when to use it, until I read a book called Understanding Aperture by Bryan Peterson.  Basically, you should use it when you are facing 90 degrees from the sun.  At noon time, the sun is directly over our head, so that's 90 degrees.  In the afternoon, the sun is to the west so if you shoot north or south, that's time for the polarizing filter.