[Harp-L] ? When to use Blues Scale or Major Pentatonic ?

["Jim Rumbaugh" <jrumbaug@xxxxxxxxxxxx>]

Thanks to Harp-l and Michael Rubin, I now know the Major Pentatonic Scale.

My Question.

Given that the chords in a song are I-IV-V, when do you use the Blues Scale and when do you use the Major Pentatonic??? 

Jim Rumbaugh