People need money in their 20s and 30s , when they are building their lifes. Buy a new house, pay school for kids, etc... At 60s-70s money isn't so important anymore, so it is not a good time to receive heritage.
The trouble with bequeathing money to people in their 20s is that far too often it gets wasted on things like cars, clothing, restaurant meals, etc.
It's much better to wait until they're 40 when they're entering the prime of their lives and are more likely to use the money wisely. Most people are grown up by the time they reach their 40s. By then they've probably learned the value of work and thriftiness.
Well, certainly give money to your "children" when they in their 40s is much better than taking it to your grave and giving it to them in a random occasion when you die, when they could be 60s-70s or even 80s already (or even dead because they lacked money when they needed or whatever)
I don't think it matters how old someone is to be honest. People who save money will save it and people who spend it will spend it. I was a penny pincher when I was a kid and I still am today. I also know people in their 70s and 80s that you could give a million dollars to and they would just use it to dig themselves deeper in debt. So part of me thinks the younger the better, although for people who aren't financially forward thinking it could be a disaster.
If you don't think the person receiving the money could handle it, an annuity is a great option.Maybe as part of a will it could include taking a personal finance class before receiving the money.