Hi all, The big difference, in my mind — as composer, arranger, conductor, and performer — is that a caesura is generally longer than a comma/breath, and intentionally interrupts the flow of the overall line, whereas the comma/breath usually doesn't (or at least doesn't in as dramatic a manner).
In musical theatre scores, the caesura is used almost exclusively when the music completely stops and is restarted ‘from silence’ in the next phrase — indeed, the caesura is quite often coupled with a fermata — whereas the comma/breath is really only used in situations where the singer/performer literally needs a little time to phrase off (either for dramatic or technical/breathing purposes) but the music [in the accompaniment] basically continues unbroken. Hope that helps add useful context! Kieren.
