I keep 500K baht set aside for medical emergencies. If that's not enough, so be it. I am not going to leave my GF a pauper by paying for overpriced, greedy private hospital treatment that may only give me a bit more lifespan. She is under instructions to get me to a government hospital if needed.
I am uninsurable, with a list of pre-existing conditions as long as my arm. Ironically, the medicos assure me none of those conditions are going to kill me.
What irks me is sanctimonious posters intoning if one does not have health insurance, they should not be in Thailand. Spare me your vacuous bletherings, one size does not fit all.