For many investors, the 24-hour news cycle brings near-constant reasons to wonder about the state of their portfolio.

As the U.S. war with Iran and the associated disputes over the Strait of Hormuz drag into their third month, for instance, you may be wondering about your exposure to oil producers or multinationals that operate in the Middle East.

And even if the headlines get you excited about buying new investments — maybe you’re stoked about advances in AI or SpaceX’s upcoming IPO — you’d probably still be smart to look under the hood of anything you’re hoping to buy as well as your own holdings to make sure that they fit within your broader portfolio strategy, investing experts say.

“Before buying any [exchange-traded fund], it’s worth seeing what its top holdings are,” says Todd Rosenbluth, head of research at investment research firm TMX VettaFi. “Then you’ll want to compare it to what you already own.”

Here’s what he and other market pros say to look for.