That's sound advice for everyone, no matter what your age.
In your 30s, make sure someone can get to your key documents in case you are out of action for a good while. That includes all your e-mail lists and web forums so they can post an announcement, if need be (see certain threads right on this forum).
In your 40s, make sure there's a second name on all your accounts. Just in case.
In your 50s, start planning for the inevitable, and make sure people know what your desires are. The really good nursing homes have long waiting lists....
I'm in a situation where I have to worry about such things. In my generation in my family, I have two sisters and ten cousins. Only three of them are married, and there is no next generation.