What are the chances of you having a heart attack or cancer? There are ways to calculate your personal risk levels, refer to:
If you developed cancer and one of the drugs recommended was not Pharmac approved in New Zealand (not paid for by the Government) the cost could be in the order of thousands of dollars.
Without adequate insurance cover where will the money come from? Will it be from friends, or family or mortgaging your home?
Also check out the Longevity calculator, Life Expectancy calculator