Sign up for automatic investing plans, which will funnel the savings directly from your paycheck into your investment account. That way the money starts compounding immediately. Plus, you'll never miss it.

Beginning at age 30, if you save $671 each month at an 8% return, you'll have $1 million by age 60. Begin at age 40, and you need to save $1,698 each month.

Key stat: 8.9 million U.S. households have a net worth of at least $1 million, not including equity in a primary residence.