Timing. Timeliness. Timelessness. 

A communicator's strategies with regard to ethos, logos, and pathos may be PERFECT but may still fall flat because they're introduced at the wrong time. A sense of kairos--being able to say the right thing at the right time--is critical to putting forth the best argument possible.

The film industry is definitely aware of kairos and makes sure to release movies at well-planned times... scary movies in October, Christmas movies at, well, Christmas...