When would you not work with someone?
If a person has deeper pain, illness, or distress that is interfering with their ability to work on changes in their present, I would urge this person to seek out appropriate professional attention for those needs before coaching with me.
If a person presents needs that are beyond my ability to understand or facilitate change for, then I would urge this person to delay entering into coaching until that need is addressed in your life or seek out a more suitable professional helper.
If a person was not able to reciprocate signals of safety, respect, and goodwill, then I would decline to enter into a coaching relationship.