re: things you really should have known about... but did not

You can set up a Roth IRA custodial account for your child who is working a job but under 18 years old. They can contribute as much as they earn into the account (up to $6,000/year).

Investing $200/month for 50 years with a 10% annual return will grow to $3.46 million (when your child hits 66 years old).

When they turn 18 years old, they take over the account.