I can't believe there's even one person in Toronto who has not paid HST, never mind "many".
Sorry you cannot believe it. Go find out how many people in Toronto get a full HST refund based on their income level, and let me know if you consider that 'many'.
What you need to keep coverage is to stay here long enough each year to have the legal obligation to file income tax, and the place you'll stay when you're here. That covers residence and time.
It amasses me how many people in Canada have no idea how their tax and health systems work yet feel so empowered to make comments.
In Canada you have 4 classes of individuals for tax purposes: Factual Resident, Factual Resident, Non-Resident, and Deemed Non-Resident. You remain a Factual Resident and have to pay Canadian taxes if you have a home in Canada (our house is rented out with a long term lease so is an asset but not a home). If you have a spouse or common law spouse and/or children who remain in Canada (his child in Canada is over 30 so not a child in this definition). If you maintain personal property or social ties in Canada. If any of these apply you MUST pay taxes in Canada. Even if you are a way for years at a time.
If you elect to become a non-resident you need to maintain the non-resident status for a period of time. One of the provisions is the magical 183 maximum number of days you can spend in Canada during a 12 month period. Gotta watch that one! At 184 days you have to pay Canadian taxes again. You get to stay a Canadian citizen, but you do not have to pay income taxes except for income generated in Canada (rental income on our house is taxable) but for most the income is low o taxes are low.
Health care, in Ontario Ohip, continues if you are in Ontario for at least 153 days in any 12-month period and maintain a residence here. Residence means you have a full time place to live. Since we rent out our house we are not delegable. There are exceptions for students and a few other groups but for retired people, that is about it. R.S.O. 1990, CHAPTER H.6 provides all the details.
So your health insurance is not related to tax at all. not even the same time frames.
HOWEVER OHIP does not cover you for most things you need coverage for when out of the country. How bad is it? If you are a diabetic and leave Canada, and go into a coma, it is not covered. (pre existing condition clause).
So who really cares? You need health insurance or deep pockets when travelling abroad.