Time for a retirement portfolio gut check?

It's an anxious time to be a patient investor. The roller-coaster Chinese stock market as well as the ongoing debt crises in Greece and Puerto Rico make it difficult to feel like your retirement portfolio is on strong footing. Now may be a good opportunity to review your asset allocation and tolerance for risk, financial advisors say, especially if you haven't done so recently.

It's time for a "gut check," said Craig Cowles, a certified financial planner and partner with Cardinal Wealth Advisors in Dallas. Answer these questions: Are you properly allocated between stocks, bonds and alternative assets in the first place? Have you rebalanced your portfolio—that counterintuitive process of selling winners and buying losers to maintain your desired asset mix—in the past year? Do you have enough cash on hand?

"Most of all though, don't become irrational and use fear as the guide, as selling low will hurt you," Cowles said. If you're tempted to sell now, he added, you most likely "had too much risk that you were not comfortable with in the first place." So it's worth taking a hard look at your investments.

Read More Is your bond fund invested in Puerto Rico?

It's important to put all the recent turmoil in the financial markets in perspective though. "The important thing to remember is that market volatility is always with us," said Kevin Gahagan, a certified financial planner and partner at Mosaic Financial Partners in San Francisco. "Specific to Greece and China, [that means] ignoring the `noise' currently surrounding the news of these events. In practical terms, for most investors, these two countries represent only 1 or 2 percent of their total portfolio—at most."

The 10 largest diversified international funds by assets have less than 9 percent of their portfolios allocated to Chinese stocks and minuscule amounts to Greek equities, according to mutual fund research firm Morningstar. (See table below.) Morningstar and Google Finance offer free tools to help investors analyze the exposure to international markets.

To be sure, stocks of multinationals, regardless of where they are based, have exposure to China and, to a far lesser extent, to Greece and Puerto Rico. But investors should focus on what they can control. "We need to step back and see what is actionable and what is not and for most investors, I don't see actionable items here except for looking to rebalance their portfolio with equities still near record highs," said Charles Sachs, a certified financial planner with Private Wealth Counsel in Miami.

Read MoreWhy catch-up contributions don't work for many savers

Rebalancing your portfolio comes with trade-offs. It can cut the risk of your portfolio and help you stick to your financial plan, but you may incur capital gains taxes from selling appreciated assets in taxable accounts as well as transaction costs to execute your strategy.

"Just as there is no universally optimal asset allocation, there is no universally optimal rebalancing strategy," according to a 2010 study on the benefits of rebalancing by The Vanguard Group. "The only clear advantage as far as maintaining a portfolio's risk-and-return characteristics is that a rebalanced portfolio more closely aligns with the characteristics of the target asset allocation than with a never-rebalanced portfolio. As our analysis shows, the risk-adjusted returns are not meaningfully different whether a portfolio is rebalanced monthly, quarterly, or annually."

So if you were happy with your investment strategy before the recent volatility, you may decide not to make any changes at all. "Often the best action in times of turbulence is no action," said Molly Bernet Balunek, a certified financial planner with Laurel Tree Advisors in Cleveland.