I'm 70 now, lost a LOT of friends to AIDS, but now losing friends to age related diseases. I do think about it. I've re-analyzed my whole belief system the last two years, and made a number of significant changes. I've had health issues, my mom's side is long lived (many over 100).. I've had two strokes, recovered well, spend a significant amount of my life exercising, eating decent. I might have 7 - 25 years left.. Although the stated of society really depresses me, and I sometimes feel I do not want to be around.
But I am going to continue to live life, and do the best I can.. Yes, it was more fun, when I was younger, stronger, handsome, but that's the way life works.. One has to change their focus and adapt. I think about death for a bit, and then decide to stop thinking about it, and deal with my life as it is now.