With fears about Zika outbreaks and terrorist incidents on every traveler’s mind, you may be wondering if you should consider buying travel insurance for your next trip.

Before you decide, here’s what you need to know about the options, what you can expect to pay, and what will—and won’t—be covered.

What does travel insurance cover? Ideally, travel insurance will reimburse most (no, not all—we’ll address that below) of your expenses if you or a traveling companion has an illness or injury that prevents you from taking a scheduled trip, if circumstances beyond your control make it impossible for you to take your trip, or if you get sick while traveling.

For instance, just because your insurance reimburses you if you get sick before your trip and can’t go, don’t assume you’re also covered if you fall ill while you’re traveling, especially if you’re overseas. That’s a different type of coverage, and while insurers may bundle them into packages to make it easier for travelers, it’s not a given that any policy you buy will include both.

What doesn’t it cover? See above—anything not spelled out in the policy falls outside the scope of coverage. Assuming otherwise is a prescription for frustration. Speaking of prescriptions, pre-existing medical conditions are generally excluded, although policies have different stipulations about what qualifies as “pre-existing.” A medical issue you had several years ago that hasn’t resurfaced, for example, might not be considered pre-existing. But, as with other specifics, your particular policy will spell out the length of time your insurance company can “look back” into your medical history.

By Martha C. White

See full story at time.com