I find this a really interesting topic, when addressing the original question. In my understanding and observation, it is intensely personal, however having said that I think it depends on the reasons, will, and motivation to overcome and ‘live life’ despite the physical/cognitive/emotional challenges that exist.
In terms of my own life, emotionally I’ve had zero reason to live for many years, having zero family and friends that I can trust or be close to without them being the ‘smiling assassins’ that mean you’re constantly having to look over your shoulder (and that’s no way to live when you’re living with disability/cognitive decline).
Physically I’ve not got a lot of reason to live, as well as mentally, because I’ve lost much of my memory, can’t work anymore, and mobilise on crutches permanently due to partial loss of sensation and strength in my legs. I also have lung, bowel, and bone marrow diseases, and chronic kidney disease. And I was hit by a speeding car which - besides other damage - rendered me unable to have kids.
Spiritually…this is the bit that keeps pulling like an ox in the field, unstoppable, unbreakable, and forever curious as to what is around the nest corner, despite the other things stacked against living on for a long lifespan. However I do not want to exist till I’m old, and I do actually have very little patience with being trapped in a junk body that if it was a car it would’ve been put in the crusher years ago.
But there’s something still in me that kicks me into gear and motivates me. I know when this evaporates, there’ll be little holding me to this trashed sack filled with old wounds that have never really healed, metal parts, and scars.
I know one day I will shut my eyes and fly away. But not yet 😉🙂