Car companies and insurance companie make money on the warranties, so on average no it is not worth it to buy a warranty. That said, insurance works the same way, so it is up to you.

Either way I would suggest you get a good independent mechanic to do a pre-purchase-like inspection on your x5 before the bumper to bumper OEM coverage goes away. That way, you can hopefully avoid some costs.

I looked into this a couple of years and came to the conclusion that Warranty Direct was the best provider but they don't provide coverage in CA. So I started setting aside a repair fund and that has seemed to work pretty well