Payments along the way.
We too, buy trip insurance, as soon as we make the deposit for a cruise. In order to get Cancel for Any Reason insurance if you want that feature, you only have a short period of time after first payment (even deposit) is made.
Then, along the way, as we book air, hotels, make payments we up the trip cost ( non-refundable) parts to the insurance policy. Say I make 500.00 per person deposits today. I will purchase my 1000.00 policy today or tomorrow. Then I add my pre cruise hotel ( ONLY if its non- refundable) when I book that. If it's 500.00 p/n I up the insurance 500.00. Then I book my air 6 months from now and add the NON-REUNDABLE part. Here is where air is tricky. If you are paying with points, the insurance will cover the redeposit fees. You won't get the "value" of the tickets refunded, just the redeposit fees. Keep that in mind. Revenue tix are different. If you purchased air for 2K, pp, 7 months from now, add the 4K to your trip insurance policy then. And so on and so on. I do this all the time. Trip insurance covers NON Refundable parts of your trip. So you are buying a policy that covers only your non-refundable parts.
Also, if I'm comparing policies on squaremouth.com for example, I choose the features in the policies that are most important to me. Evac coverage ( high), delayed bag ( paying $$ after short delay). High medical coverage. You can search the details in each policy for the important things to you. Cancel for any reason if you find that important. Thats what I've always done. Works if you understand exactly what you are doing.
Make sense??