Say an overly-dependent person comes and asks for your help. And you feel that it's not your job to do things for her, so you make a suggestion, "Why don't you try xyz?" Your aim is to help her help herself and stop asking you. But each and every time you make a suggestion, she tells you why it wouldn't work and how her situation is infinitely hopeless. And this back and forth will persist until you give in and offer to do things for her.

At what point do you say, "Hey I'm maxed out on my suggestions. You are on your own"?

Next time, should I just say from the beginning, "No, I can't help you, sorry" rather than suggesting her to help herself and get myself trapped into this kind of conversation? Or if that's too cold or harsh, should I limit it to just one suggestion and say, "Well I tried to help you but I can't think of anything else"?