Here in the U.S., you can slice and dice trip insurance to give you peace of mind where you need it most. The prevailing thought though is never take cruise or airline insurance off the bat (usually comprehensive which is combo trip cancel/interruption/medical). You can shop online for more cost-effective options.
Most of our travel is international with multiple trips a year. We get an annual multi-trip medical plan for less than $500 with good coverage (though coverage is usually is reduced though for anyone over 70). I'm too risk adverse on the medical because of age, physical condition and klutziness. Most U.S. health plans (including Medicare) don't cover ANY overseas illnessess, accidents or transportation.
For trip cancel/interruption, I only price for trips over a certain $ amount that would hurt should I have to back out before or during the trip. I mean, we're talking Regent here. Cruise fares in certian classes for extended voyages run in the tens of thousands per person. That would be a big hit to the wallet. To keep trip cancel/interruption insurance manageable, I price WITHOUT including airfare. If we had to bail, even on a non-refundable ticket, we could bank that cost as a credit to use on the same airline over the next year---which usually isn't a problem. So any claim filed, would only be on the cruise fare only.
Insurance coverage: You do not need it until you really need it.