Although we always purchase cancellation insurance we have used it but once. A family member was invited to join us on a cruise as our guest but she fell ill and could not make the trip. Although we did eventually collect the value of the lost fare, it took almost a year to do so. The number of required forms and doctor certificates were ridiculous. We persevered only because of the principle of the thing. But the cost of the insurance was deducted from our account with lightning speed...
A point we would like to offer is that with some credit cards, their use for the purchase of the cruise fare will result in giving you free cancellation insurance up to a certain dollar value. Check this point with your card issuer.
When we purchase insurance, and always from a source other than the cruise line, our agent deducts this free credit card insurance value from the overall cruise cost and insures only the balance of fare cost. This has resulted in many a saving. However you cannot apply this breakdown when you purchase insurance coverage from the cruise line itself.
No health insurance is involved in these transactions as we have personal coverage for that. FYI