Just like retirement savings goals, it entirely depends on the family and what they value. There is one key factor that I like to remind my clients: Your kids can borrow money for college, while you cannot borrow money for retirement. Remember that.
The parents' (or parent's) obligation is to ensure that they are self sufficient in retirement. If you don't plan appropriately to take care of yourself in retirement, you could ultimately become a financial burden on your children.
If funding their education is that important to you, you could still have them take student loans and commit to repaying them, on their behalf. The point is, there are options for financing college - there are no good financing options for your expenses in retirement.
