Job is indeed a major factor. I don't currently work in a great place - it is generally a rather toxic place - and age-discrimination is, like most of the industry, rife. Pushing 54 it is hard to find a new gig, especially in this market, which doesn't help at all. After 30 years working at the forefront of this industry solving some of the hardest problems around, my skills, experience, and insights are just no longer required.
Life circumstances have left me without any kind of options for retirement, early or otherwise, so this is me for the rest of my life; I'm likely to die behind my keyboard. I'd rather go out on my own terms, watching the sun set behind the sea.