The stock market, which has had a volatile year, is plunging again. The Dow Jones industrial average fell over 700 points on Tuesday and the S&P 500 dropped 2.8 percent, as traders fretted about a possible economic slowdown and trade between the U.S. and China.

But for the average person, shifts in the market, even ones as dramatic as the ones we've seen this year, shouldn't be cause for panic. During times of volatility, seasoned investors Warren Buffett and Ray Dalio agree that it's best to stay calm and stick to the basics.

"Don't watch the market closely," Buffett told CNBC in 2016 amid wild market fluctuations. "If they're trying to buy and sell stocks, and worry when they go down a little bit … and think they should maybe sell them when they go up, they're not going to have very good results."

Buffett emphasized that holding onto investments long-term is crucial to having them pay off. "The money is made in investments by investing and by owning good companies for long periods of time," the Berkshire Hathaway CEO told CNBC. "If they buy good companies, buy them over time, they're going to do fine 10, 20, 30 years from now."

Dalio, the founder of investment firm Bridgewater Associates who is worth an estimated $14.5 billion, agrees. Though it's tempting to sell when the market begins to drop, he says, giving in to your fear is not a sound strategy.

"You can not possibly succeed that way," Dalio said at the Harvard Kennedy School's Institute of Politics. "You've got to do the opposite. It's when you're not scared you probably want to sell, and when you are scared, you probably want to buy."