It's always a good idea to buy insurance that covers trip cancellation and interruption, but even more important is emergency hospital and medical insurance, which protects you against the astronomical medical bills that can be racked up should you require treatment in another country. Bills for medical professionals' fees, hospitalization, drugs, X-rays, diagnostic tests, dental treatment, and ambulances can add up quickly.
Some Canadians are under the impression their provincial health plan has them covered while on vacation. This is only partially true - provincial plans provide plans provide only a small fraction of costs of treating illness and accidents outside Canada. Depending which province you live in, your government health plan coverage is capped at rates between $75 Cdn. and $400 Cdn. a day. But in the United States, a typical hospital will charge $1,800 - $2,000 a day, and as much as $10,000 per day for intensive care and complex cases. Without travel insurance, a serious illness or injury can not only ruin your vacation, but it can leave a huge financial scar.