As I was sailing along in my 60's and 70's, I thought that I'd be able to continue in this manner forever. No need for knee replacements, etc.. Now in my late 80's I've slowed to a crawl. Need a damn cane to get around. Naps becoming more prevalent. Forgetfulness becoming a part of everyday life. Good hearing starting to diminish.
All of this just crept up on me WITHOUT some dreadful illness or injury.
Enjoy the brightly burning light, while you can, but don't bet on it staying bright until the end.