To be honest with you, it depends on the age, and type of cry. If it's I need you now type of cry.. then be there. If it;s a newborn, then provide support. But if it's an older infant, who knows how to self soothe, and it's just a fuss or a call out cry at night.. then I hold back. But if it turns into a I need you! then I'm there.
It's really a judgement call!