You have to compare insurance plans and decide on your own what you want to be covered for. If you don't know this answer yourself, best option is to get an insurance agent to help you explore the different options and how much each will cost you.
Health care is very expensive in Canada if you have to pay for it yourself. So you want to make sure you take insurance to cover yourself for emergencies. Normally insurance providers will not cover anything related to pre-existing conditions.
Typically insurance also does not cover any non emergency care. So you need to be prepared to pay for all of that yourself / out of pocket.