What are some personal finance mistake(s) your parents made in their younger selves which you would like to avoid?

Not saving for retirement / putting us in a sandwich generation.

Let's not penalise them so badly, maybe it is a case of not they don't wan to, but they cant. e.g. my parents had no insurance, not because they dont wan to, but they earn too little to even get by with daily living

Didn't retire plan or have any insurance, only reach enuf to pay 100/mth for cpf. So since my 20+, I plan to help them earn passive income (rent) (for their spending/medical) when I'm older and really thank God, my plan worked.

SS

Making minimum payment for credit card and letting the amount roll