The words “old” and “young” get used here a lot, but it’s more complex than a human would think. My language (and all the other languages I know of on Darisa) have two different words for both “young” and “old” with differing meanings.
For a human, I can see why you don’t need two separate sets of words. You’re tied to a single body for your whole life, like an animal, so if a person is old, so is their form. The age of a kukun’s body has nothing to do with how long they’ve been alive as a whole. With just one set of words, that is really hard to communicate very well. Someone very body-young could be very, very experience-old, if that makes any sense. Etlu’s body is young each time they persist into a new life, and from what I can tell, they are ancient.
Generally, trends tend to follow people’s body-age more than the total time that they’ve been alive. If you’re in a young body, you’re going to like doing things that it’s fun to do when you have a lot of energy and can party hard, or play very tiring sports, or any given thing. For someone with an older body, more low activities will likely be their focus.
In any given life, you’ll miss some trends and fads aimed at those with a different body-age than yourself. It’s also worth noting that there are “waves” of generations. You’ll probably be in a young body around the same time as everyone else your body-age next life (since most people tend to persist when their bodies get creaky). This means that you can count on old trends getting revisited and reimagined around once per life.
Persisting much sooner or much later than you usually do can throw you into a different “wave” of people and is a bit disconcerting. That happens to everyone at some point or another, though. Whether it’s from some medical issue that it’s easier to just solve with a new body, or if you’re just very busy and have to hold off from persisting to complete some important business, you’ll just find it happening from time to time.