There are annual out of pocket maximums. Mine is something like $7000 last I checked. Its a lot of money, but not an amount that would bankrupt most people.
Talk to somebody who has a chronic illness or multi year cancer. There are plenty ways to charge people way more than their out of pocket maximums. People also get worn down by constant mistakes and weird bureaucratic hurdles by hospitals and insurance.
I always wonder about those. Are they real? Or will insurance companies find exclusions or ways to mark things as out of network and the maximums don't apply?
