I went through a serious bout of cancer when I was 30 and saw what it looks like trying to fight the inevitable. I've been cancer free for about 9 years now, but the suffering I went through and saw in others left its mark on me.
When I do finally get sick again, I will go out on my terms, not the disease's.
I have a book about this, and I think it's good to plan ahead.
I'm also too scared to read the book because I struggle with suicidal thoughts, and I fear I might make the decision too soon, when I'm in fairly good health.