Ask if your White Mage needs MP.

if yes
Cry because you do slightly reduced damage.

if no
Ask if your SMN needs Foe's Requiem

if yes
Is Battle Voice up?
if yes
Think about it, but finish your opener first because you matter :)
if no
Play Army's Paeon because you matter :)
if no
Play Foe's Requiem anyway because you're a good support :)

If BLM asks for Foes Requiem
Ignore his request completely because there are more important thin than BLM dps

else
Turn off Wanderer's Minuet because running around is more fun than DPS :)