Don't mean to make it sound like a terse answer, but the honest answer for me is "Don't know, don't care". I keep it all in context for sure, because there are people who have it far, far worse than I do. But I have health challenges of my own, so I don't even concern myself with how long I'll live. Every day above ground is a good one. If I live to see 90, awesome. It it's 50, then that's what it is. The only reason I'd care is for the kids. I want to be here as long as I can for them, or at least until they're full grown adults. To that end, I go to great lengths to take care of my body, I work very hard at it. From there, what will be will be.
Father time is undefeated, so when I lose, I lose.