"Ask, 'Has my portfolio become unbalanced, because my equities have completely taken over the garden?'" Ballou said. "It's time to do some pruning and take some money off the table."
Gauging your tolerance for risk is especially key. For more risk-averse investors, forgoing some gains now might be preferable to the pain and panic of a market downturn, certified financial planner Mark LaSpisa, president of Vermillion Financial Advisors in South Barrington, Illinois, told CNBC.com earlier this year.
"The real question is, for the person that hasn't experienced a correction in the past nine years, how are they going to react?" he said.
Depending on your goals, strategically shifting your investments could help reduce risk and still meet return your objectives, LaSpisa said. For example, he said, an investor who only needs 3 percent to 5 percent to meet retirement income obligations — and has already benefitted from several years of above-average returns — may not need to chase double-digit returns or stay in riskier investments to achieve that goal.
"Why are we reaching for that return if it's not needed?" LaSpisa said.
Keep goal timelines in mind, too, both for current investments and money you're thinking of investing, Douglas Boneparth, a certified financial planner and president of Bone Fide Wealth in New York, told CNBC.com earlier this year.
"Long-term goals, the ones that are seven, 10 years plus … it's easier to remain unemotional because you have time on your side," he said.