When preparing wills and enduring power of attorney documents, it's a great time to consider related matters. To some degree you're already thinking about the worst that could happen, so you might as well do everything "while the bonnet is up".
One exercise worth working through is developing an advance care plan. An advance care plan documents your thoughts regarding the care you want towards the end of your life.
It's a valuable thing to do, regardless of your age or health situation.
You might argue that the younger you are, the less relevant such a process might be. And it's certainly true that for most chronic health issues (for which advance care planning can become especially important), age is a major risk factor (if not the major risk factor).
But you never know what might happen to you.
An advance care plan will evolve over time. The earlier you start to think about these matters, the more time you give to let these issues incubate, so that over the years you can develop a personal, deeply informed view on what you might want to do.
Another advantage is that it puts you in a position to discuss these issues with other people. You can discuss these issues from your perspective, in terms of what you want to happen. But it also makes it easier for you to discuss them with other people who are important to you. Which may include people such as your parents and grandparents, for whom such an exercise might not be so intellectual.
A fantastic resource relating to advance care planning is http://www.advancecareplanning.org.nz/. This site provides some terrific resources explaining what an advance care plan is, what you might want to consider and discuss with others, and how to document such a plan. It includes online modules which can guide you through the process and template documents that you can work through.