Question: I'm booking a Europe trip with my family. The tour operator is pushing me to buy a travel insurance policy. Do I really need this? If we can't go, won't they just reschedule us on another trip?

— Katie, Santa Monica, Calif.

Answer: Sorry Katie, but without that travel insurance, if something goes awry in your life you're out of luck. First there's the airfare. Plus you've got the tour cost. If you're willing to risk all that, then go bare. But here's my tale of caution:

A few years ago, I had a heart-breaking letter from a man who had booked a cruise for 30 as a family celebration. His young son had been diagnosed with cancer and the family needed to stay home to deal with his treatment. He had not taken out travel insurance and wanted the cruise line to reschedule his trip, though the terms of booking clearly stated that would not be the case without insurance. And while he felt the company should understand his situation, the company had been clear in advance on the terms. Bottom line: He was out thousands of dollars.

My rule of thumb: Any time you’re putting up a substantive amount of money in nonrefundable expenses, you need to take insurance. That goes double if you have elderly parents who might get ill or if someone in your party has had medical issues. At the very least, it provides peace of mind.

When it comes to tour companies and cruise lines, most of them offer policies through third-party insurers. Airlines do as well — though the circumstances they cover can be very, very limited. Before you buy, read details closely and shop around. InsureMyTrip.com, squaremouth.com and quotewright.com are great websites for comparing policies and prices. Most of the comprehensive policies offered include emergency medical and emergency evacuation, along with lost luggage, trip delays and cancellation for covered reasons.

That last factor is critical. Be sure the reasons that concern you most are covered. Some policies define grandparents as immediate family, for instance, but not Uncle Charlie. Others include getting laid off from your job while others don’t. Only a handful will let you cancel your trip if a hurricane is heading this way — and most of those fall under “cancel for any reason” clauses.

There are two other key factors. One is pre-existing conditions — whether you’re covered if your diabetes flares, or your previously examined cranky knees just plain give out. (Most policies will cover pre-existing conditions if you buy insurance within one or two weeks of your first trip payment.)

Another consideration: whether you want primary medical insurance — it pays first no matter what — or secondary insurance that pays only after your regular insurance ponies up. (And that can be a long wait.)

Of course, if you’re traveling on air miles and got a really cheap deal on your trip, travel insurance might not matter to you. But you do want to check it out.