When you're too old to support yourself and you need to rely on the help of other's to live life. Such as being too weak to pick up your spoon and eat, walking is too strenuous on your body (I rather die young and happy not old and horrible. Of course a shot to the head isn't what I want, being medically put down is preferred or going out in a crazy manner. Like jumping into a volcano while riding a shark strapped with dynamite. ), or have a chronic illness that will kill you in X amount of time. Other than that never kill yourself, cliche but it will get better with time.