Is there some point from your perspective
when the quality of life could be so bad you'd give up ?
and the line you draw today , Does it change ? as your current quality of life slowly deterioates ?
Let me think of some things that would effect my purview on my way of life....
i) loss of bowel control
ii) living in an iron lung
iii) alzheimers or similar brain disease
anything that would effect my autonomous functioning as a human being. (what about christopher reeves ? a special case no doubt, but if you or I ended up that way we'd be doomed) but would you fight to go on ?