A comprehensive insurance is a good complement to your liability insurance. It covers unforeseen damages to your drone and/or your related equipment. The cost for the insurance differs due to the value of the drone as well as how you use it.
Around The Clock
Your drone and all related equipment are insured all the time no matter if you fly or not.
Flight Time Covered
You can get the insurance only when you fly. All other time it is not covered by your insurance.
Flight Time + Transportation
Same conditions as above but with the difference that you drone and related equipment are covered during transportation. It covers damages and/or theft.