For more general info/suggestions/etc., about travel insurance, you might want to check the CruiseCritic section about that; much of the content is not cruise-specific:

https://boards.cruisecritic.com/foru...vel-insurance/

Also, we use a travel insurance broker (no extra cost for using them):

www.TripInsuranceStore.com

They were incredibly helpful when we first starting learning about all of that.

We always get a policy that works as 747FC described. We start the coverage for the deposit, and then up the coverage as we have additional non-refundable payments, be they hotels, cruises, tours, and also the change or cancellation fees for airline or awards tickets.

Note that to get the broadest coverage, including pre-existing conditions or CFAR (cancel for any reason, though this part does cost extra), one usually needs to book promptly after making the very first payment, non-refundable or not.
But there is at least one insurer who offer those features if one books within 24 hours of *final* payment (defined very narrowly of course). The coverage isn't quite as good, and the CFAR costs a lot more.

The above is for residents of the USA. TIS also now handles coverage for Canadians, which I hadn't realized.
Also, there is some variability in coverage available, among the states, so it's important to make sure that you match that when inquiring.

We've had several claims, and Travel Insured (the insurer we use through TIS) has paid with out requiring any documentation that we felt wasn't really necessary. Very matter of fact, unlike reports we've read about a few other insurers.

GC