If you're booking a holiday getaway, your travel agent will probably ask whether you want to protect your trip with insurance. Travel websites make insurance an even easier click-to-buy option. 

About 30 percent of globetrotters buy travel insurance, and the coverage has become increasingly advisable today. In the 1990s, just-the-basics policies were the norm. But now, travelers can protect their trip against infectious diseases like Zika, hurricanes, natural disasters like the recent earthquake in New Zealand, and civil unrest like last July's coup attempt in Turkey. 

And terrorism. In the wake of the deadly 2015 terrorist attacks in Paris, travel to Europe is down, and online searches for terrorism coverage by Americans traveling to France have gone up 192 percent since last year (to Spain, up 226 percent, and to Germany, up 256 percent). That's according to SquareMouth, a leading travel insurance comparison shopping website.

Such protection is not always standard, so read the fine print and ask the insurance agent to make sure the policy you're considering will protect you.

Insurers generally offer three classes of policies: basic, midlevel, and premium, with the comprehensiveness of coverage and price increasing accordingly. Cancel-for-any-reason policies give you the most flexibility and the best option to back out over fears about terrorism anywhere in the world rather than just on your itinerary.

Travel insurance is a comforting concept, but the devil is still in the details, and that creates lots of opportunity for sales representatives to sell you false security. To avoid that, size up the deal by asking six key questions.

1. How many choices does the seller give you? If you buy from a travel agent, you'll probably be offered only one or two policies from one company, and "best" usually means best for the travel agent in terms of how much of a commission he or she collects on the sale. Online travel sites also tend to limit your choice.

We like independent travel insurance comparison websites like InsureMyTrip.com (800-487-4722), which sells more than 250 policies from 29 insurance companies, and SquareMouth (800-240-0369), which offers 112 policies from 21 insurers. Choice is important because it allows you to buy as many or as few features as you want. If you're not sure what you need, we recommend that you use these websites' old-fashioned toll-free numbers to get precise guidance from one of their human agents.

2. Is the insurance too cheaply priced—or overpriced? Real travel insurance costs 7 to 10 percent of your prepaid nonrefundable costs. So if your upfront airline tickets, resort hotel, cruise, and/or family tour package charges add up to, say, $8,000, travel insurance can cost $560 to $800. Travelers over age 40 may pay more, along with those taking longer trips and those wanting more comprehensive coverage. The $10 to $25 impulse-purchase policy is very thin on benefits and may only provide death benefits, which you don't need if you have economically priced term life insurance.

At the other extreme, watch out for overpriced policies, which can appear when your travel agent has a captive customer—you. The best way to know whether you're overpaying is to shop around.

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3. Can you get a waiver for a pre-existing medical condition? Trip cancellation (before you leave) and trip interruption (during your trip) are key reasons for buying insurance, and 80 percent of claims are related to medical problems. Unexpected injury and illnesses are, of course, covered. But if you consulted your doctor about a problem 60 to 180 days before your trip and that problem comes home to roost after you buy your travel, that would be an excludable pre-existing condition. 

To be eligible for a pre-existing medical condition waiver, buy your travel insurance within 10 to 14 days of making your first payment for your travel, says Jim Grace, CEO of InsureMyTrip.com. "If you're 90 years old, get the insurance the same day you buy your trip, just to play it safe," Grace said.

4. Does the policy provide healthcare? If you're traveling overseas, your health insurance may or may not cover your care. Medicare typically doesn't cover you outside the U.S., though some Medigap policies do. "National healthcare programs don't cover noncitizens, and Obamacare does not cover you overseas," says Jim Krampen, co-founder of Seven Corners, a travel insurance company.

So travel insurance may be a wise buy for its healthcare benefits, which you can buy as part of a comprehensive policy or à la carte. Although most trip cancellation/interruption coverage requires little or no deductible, travel healthcare coverage gives you the option of a zero to $1,000 deductible. Of course, the lower the deductible, the higher the premium. Be careful about payout limits, too. Some policies limit benefits to $10,000, which may not buy much healthcare.

5. What about medical evacuation? Medical service is only half of the travel healthcare equation. The other half is getting to that medical care. The more adventurous, exotic, and remote your travel is, the more it will cost to transport you to competent medical treatment. For example, after a tourist was attacked by a lion in Zimbabwe and suffered neck, back, and leg injuries, she needed to be evacuated to Johannesburg for surgery via air ambulance, then back home to the U.S. on a commercial flight with a rescue nurse.

A commercial-flight with a rescue nurse can cost $10,000 to $50,000, and an air ambulance can cost $20,000 to $250,000, depending on where you need to be picked up, where you have to go, and the type of medical crew. We think medical evacuation coverage is well worth the price of about $200 to $300 for one trip à la carte and $200 to $250 for an annual plan for frequent travelers.

Your chances of needing such service are remote, of course. Almost 74 million Americans traveled internationally in 2015. And On Call International, a leading travel risk management provider, managed more than 15,000 medical cases, including more than 1,500 medical transports, through its 24-hour, 365-days-per-year service, which connects to a network of 4,000 medical centers and air ambulance and commercial medical transport providers worldwide.

6. What don't you need? “Don’t buy insurance that covers small, manageable losses or only a slice of risk,” says Bob Hunter, director of insurance for the Consumer Federation of America. For example, losing some of your belongings won’t break you financially, so keep a close eye on your valuables and be ready to accept losing less-valuable stuff. And if you’re worried about dying in a plane crash, buy term life insurance, which covers you no matter how you die as long as your policy is in force, rather than flight insurance, which only pays benefits if you die in a plane crash and covers you only for the short time you're flying.