The usefulness of the T-year to calculate ages is another one I've wondered about. Is there any actual physiological justification for using that as the primary standard? It's so engrained it's hard to even question. Under the age of 5 or 6 it's really much too long to tell you anything much, and over 25 or so it's much too short, and in between is just a massive roiling chaos anyway. Let's all switch to Martian years. Or a logarithmic system for ages. That probably actually works best for human growth cycles! Your age starts at 1 when you're born (like the Korean system) and then you calculate log₃(age in Earth years) * 10 and that's your actual age.