Insurance policies for boats differ for many reasons. The age of the boat, the condition of the boat, and where the boat will be housed during the year are all factors that will affect the insurance boat policy premium. As boats age, they will begin to decrease in value. This is the same of most vehicles.
This means that each year, your premium should be a little lower. You should either take out a new policy each year or renew your current policy depending on the premium you are paying. Insurance boat coverage will vary from company to company, so it is worth it to see what is out there.