Share 'To tyvek or not to tyvek... that is the question'

Lately I have been seeing & getting numerous questions on the use of WRB’s or Weather Resistive Barriers. For example; do I need it if I am using foam? If I am installing foam, should it be placed over the foam or under it? According to the ZIP system, I don’t need one, is this really a good way to go? Then of course the ever famous should I use tar paper or Tyvek? Needless to say that sounde…