Some insurers refuse to pay medical or any other expenses associated with particular activities. Aside from pre-existing medical conditions, common exclusions also include anything that happened to you as a result of an act of war; suicide, attempted suicide, self-harm, anything that you caused by doing something illegal anything you did while drunk or high, anything caused by a sexually transmitted disease (excepting ones you have covered as a pre-existing condition), any accidents you have while participating in an adventure sport not specifically listed as covered, anything caused by negligence on your part, any theft or damage to your belongings where they judge that you weren't looking after them sufficiently well.

Some policies may exclude all coverage in certain countries or regions within countries. This is usually due to danger or serious health issues. Check the fine print of your policy, e.g., in one section of the policy it may explicitly list a country as eligible for coverage, and then in another section exclude coverage in any country listed on certain government websites, such as the World Health Organization or Britain's Foreign and Commonwealth Office.

Some policies have an excess amount (also called a deductible), which is deducted from any claim you make, so that you will be paid the amount of the claim minus the policy's excess. In general, the lower the deductible, the higher the insurance premium. Travel insurance with a $5000 deductible can be as little as $10/month: that means that it will not cover minor expenses or even a mid-level problem like a broken wrist, but it will be a financial lifesaver if you have a serious accident.

If there's any chance that your trip might extend beyond the period of your insurance, make sure that you know in advance how you can extend the policy and whether you can do this while traveling. It is generally much easier to extend a policy if you request the extension while you're still covered: obtaining a policy when you're traveling but aren't presently insured is difficult. In addition, if you let your policy lapse you will obviously not be covered for anything, including medical expenses, while you arrange a new policy. Many policies require that you apply for an extension at least 7 days before your policy expires.

When planning a trip, pay for your policy to cover a few days after your intended return. In the event of last-minute delays or changes of plan which extend your trip, you then have a few days to sort out any extension of the policy you need. Some policies will automatically extend if the delay is part of a problem that you could claim for: for example, if you have insured against delays and the delay extends your travel past the end of your coverage, the policy is automatically extended. This will typically not apply to pre-existing conditions or to high risk travelers such as the elderly, even if you fully disclosed pre-existing conditions when applying for cover.

Extensions to your policy are never guaranteed to happen. They will always be at the discretion of the insurer and may be refused based on your previous claims and any other information that you disclose when applying for the extension (and you will usually be required to disclose anything you think might be relevant lest the policy be void). Some insurers treat all applications for an extension as an entirely new application and will re-evaluate your circumstances before insuring you. Medical problems that occur during your holiday may count as pre-existing conditions when applying for an extension and certainly will if applying for a second policy.