As you approach retirement age, most experts agree you should gradually shift more into bonds to protect the money you've accumulated. But retirement can last a few decades, so it generally pays to maintain a healthy dose of stocks well into retirement: possibly between 40% and 50% while you're in your 70s, and up to 30% when you're in your 80s.
If you want to put your asset allocation on autopilot, consider "target-date retirement funds," which are available in many retirement plans. You simply choose a fund that's labeled with the year you intend to retire, and it will automatically adjust what it invests in (usually a mix of stocks, bonds and cash) to maximize your return and minimize your risk as you get older.
For an idea of what the right mix of stocks and bonds is for you, go to our asset allocation calculator.