Fifty? Pfft, sure! I'm almost there, and yes, I want to continue… Now Sixty… I'll confess that my evil "plan" from many moons ago was to—by then—be able to balance this with my other loves, being outside and moving (not just my fingers). I suppose many professions suffer from the same disadvantage, but programming is a slow killer. Eyes, joints, all that clot-inducing sitting, disrupted cicardian-rhythms, too easy to get trapped in bubbles disconnected from reality, you need to be extra-vigilant and pro-active if you care at all about your health and those that love or at least put up with you.
I definitely feel this. I'm only 24, but already I can feel the effects of being in a chair for 8-16 hours a day. It's sad that it is happening so quickly, but it has really made me realize how much I need to break the cycle and start thinking about this now, rather than just deferring it till when I have time.
Also I deeply feel the mental bubble that forms around me when i'm programming. It makes it scarily easy to just start withdrawing from other people and the world around me.