The stylus that comes with a Nintendo DS is a very mild form of hand torture. Not sure whose hands those were designed for, but not mine. In googling for a good replacement, I chanced upon a blog post which suggests finding a nice big ballpoint pen and jamming a DS stylus inside so just the tip sticks out. This works amazingly well. It's not as portable, but I will make that sacrifice to prevent being crippled.
I am in fact always a bit worried about preserving the health of my hands. I have no hard data to support this, but I suspect my generation may have major hand-related problems in the coming decades. What with computer keyboards and tiny cell-phone and PDA keys and lots of other techy things. Many of us use our hands to communicate almost as much as our voices. Until we have Star Trek voice-recognition software, this will be a problem.
I started experiencing a lot of aches and pains in my hands and wrists a decade or so ago, and I attributed it to computer use. Since I started paying more attention, things are better. I maintain a very comfortable typing position for my hands. I have a nice big comfortable mouse. And so on. My hands don't hurt any longer nowadays, which is nice. If I become unable to type someday, I'm completely screwed. How can I work as a programmer if I can't input text into a computer? And I won't be able to draw or do origami or play video games or do many other things I enjoy.