With a spouse or partner, the useful starting point isn't "how much do you earn" but "what are we actually saving for, together." Aligning on shared goals — a home, a child's education, retirement — makes individual money decisions (how much to spend on a vacation, whether to change jobs) much easier to navigate, since there's a shared reference point.
With ageing parents, conversations about their savings, insurance, and end-of-life documentation (like a will and nominations on their accounts) are uncomfortable but important to have while everyone is healthy and thinking clearly, rather than during a medical emergency when decisions get rushed and emotional.
With adult children, sharing the basics of how you manage money — not necessarily exact figures, but principles like the value of an emergency fund or how compounding works — tends to be far more useful preparation for their financial independence than shielding them from the topic entirely until they're suddenly on their own.