Insurance is never cost-effective. That's how insurance companies make money. And they're better at math than you (or me, or just about anyone), so they're pretty good at making sure they make money.

That said, insurance is still a good idea in general if you otherwise couldn't afford the cost of whatever's being insured, e.g. your house burning down or something. That's the tradeoff; you'll likely give them more money in the long run, but you're protected from sudden catastrophic losses.