I’m 35, an investing newbie and putting 10% of my salary in a 401(k) — should I just put everything in the S&P 500?

Investments in the stock market are key for growth in your retirement portfolio. But advice on how best to invest is rampant. How can you ensure proper diversification? Imagine Charlie, a 35-year-old man who hopes to retire at 67, in time to qualify for the standard Social Security benefit. Charlie is currently making $50,000 per year and investing 10% of his income, plus earning a 100% employer match on up to 4% of his salary. He's also expecting to get a 2% salary increase annually from now until retire ...