For every vehicle, appliance. tool, electronics, etc etc that you buy and that someone tries to sell you an extended warranty ---
take the insurance (warranty) cost and put it into a 'self insured' bank account.
If there is a failure -- AND --- the failure would have been covered by the package you didn't buy --- take money from the account to pay for it.
If the package wouldn't have paid for it, then don't use the account.
There is a chance that early in this 'self insured' program that the account may have a negative balance.
When you retire and have a significant balance in the account, you'll be able to celebrate that it's you that has the money and not the people/companies selling the packages.
Those that sell these packages don't do it because the program loses money.
Even after printing literature, paying sales commissions, perhaps a few failures they have to cover, etc etc
OTOH, it's your money, and if you sleep better spending some of it, then go for it.