"How are you?" - when to ask, when not to ask?

When to ask "How are you?":

when meeting someone I care about or are concerned about, when I am ready to listen, pray, help, invest more into that person, especially when meeting people, who have shared with me challenges of their life, and which I accompany in their walk through it.

When not to ask "How are you?":

When I have no time to listen or no strength to care, when I have no help and no solution to offer, when I see that the person is hurting or depressed.