On Thursday, November 23, 2017 at 12:46:19 PM UTC-5, LAX wrote:
Is everyone insured by Costello Insurance?
I am purchasing a glider and it comes down to this, the annual premiums I was quoted are approximately equal to the cost of the glider divided by 16.. That is my annual payment. In other words, if I don’t have insurance, every 16 years I could buy a new glider with the money I don’t on insurance.

Not everybody is with Costello. I happen to be and pay less than the rate you are quoted, but I've been with them for more than 20 years and have a very good claims history. Rates and deductable do go down a bit over time.
Service is superb. Claims support excellent. They have a number of features that you may no be able to get from others.
They are unlikely to be the cheapest.
Good Luck
UH