Sure, travel insurance can come in handy if you have to cancel or cut short a trip.

But don’t get nailed by the dreaded pre-existing condition exclusion.

Remember, every insurance policy is different, so there is no rule of thumb.

But many travel insurance companies won’t cover claims if the traveler, a companion, or a family member has a pre-existing illness or injury.

In most cases, the medical condition cannot have commenced, worsened or required treatment within a certain window of time. That could be anywhere from 60 to 180 days before the effective coverage date.

Now, some providers actually have something called a Pre-existing Medical Condition Exclusion Waiver.

To take advantage of that, you have to purchase the policy within a certain period of paying for the trip in full … usually within 14 days.

One of the biggest mistakes I see people make is not asking enough questions.

Don’t just take your travel agent or tour company’s word for it.Call up the insurance provider directly and go over specific scenarios to learn what will—and won’t—be covered in case of emergency.

Find out great questions to ask in our Travel Insurance section.

And check out the rest of our Daily Travel Tips here.