The Charles Schwab survey found that only 10 percent of 401(k) participants whose employers offered third-party investment advice as a benefit actually used the service. Of those who did take advantage of the offer, 70 percent made adjustments to their plans that nearly doubled their savings rates. Those who received professional guidance also had more diverse portfolios than those who did not.

Before you make an appointment with your company's investment adviser -- or seek one out on your own -- do a little self-assessment. McHugh says you should be prepared to answer questions about how much you have saved -- within your company retirement plan and elsewhere -- as well as your expected retirement age and your anticipated retirement lifestyle.

Of course, you'll want to get advice on your asset allocation, but Lane says you shouldn't leave the choice entirely to the pros.

"If they make a recommendation, ask them why," Lane says. "If they are just basing it on time frame and not the amount of volatility you're willing to accept, really push back against that. You don't want any cookie-cutter answers."