You have to purchase it annually. The insurance company will reassess their rate and decide if they qualify for supervisa insurance annually. What is considered as a preexisting condition and what will no longer be covered can also change annually. If people have a more medical emergency or a major change in their health while in Canada they may struggle to get supervisa insurance especially at an affordable rate. Their supervisa insurance may also no longer provide coverage for their most likely health emergency so it also may not make sense to remain in Canada as a visitor.