Yesterday, I used Google Hangout to help my son set up his 401k. He's living the dream in Silicon Valley and wants to make good financial decisions. He already knows to never carry a credit card balance, to spend less than he earns and to invest in low cost indexed equities.
First, how much to save. Although he probably can save even more, we agreed that if you save 10% a year, keep it invested aggressively and don't ever withdraw a dime until you retire, you will do well.
Next, Vanguard defaulted him to a "Target Retirement" plan. Not a bad choice but at age 22, why waste away any of your 401k in bonds. In long term investing, cash is the scariest place to be, followed close behind by bonds. After inflation, cash loses money - sometimes a lot of money. In the 70s, cash lost half its value in less than ten years. I know, because his grandparents' retirement was decimated in that decade. Historically, bonds gain about 1% after inflation. That is, they double in value about once a generation.
Meanwhile, equities will return multiples more. I did some quick math for him and figured that in forty years, his bonds might go up about 50% but his equities will not just double or triple (after inflation), but will probably do this more than once. That's the earning power of investing in businesses that work hard every day to get the maximum return on your investment.
So instead of a target fund, he bought into three indexed ETFs: US equities, developed international equities and emerging markets. He put 60% into the overbought US market and 20% into each of the foreign markets. I suggested that he rebalance every year or two. Then when he's 40, he can look at buying some bonds as insurance for an equities catastrophe. That's it!
He sent me a screen shot of his completed form and then hit the enroll button. He's on his way to a safe and strong retirement, just a month into his first job.