I give out com easily if I am tank I give to healer, if I healer I give to tank and dps to dps. The person doesn't have to talk as long as I am not annoyed by anything they do, then they get the com.

Like I was with a SMN who did not seem to understand what bane does and they are at 50, they don't get the com so I would give to tank or healer. Then when I tank the healer will usually get the com, quite hard to mess up healing too much. Then when I heal I guess it'll have to depend, is the tank pulling too much when the party does not have the aoe power to kill everything too fast, or worse pulling big in a low lvl roulette. If the tank is losing aggro I usually don't care too much if they are way undergear compare to everyone else.