We discuss these borders. And a lot of rules apply to this but you still need the basics as a good international health insurance. I believe there are countries where it is illegal not to have any insurance at all. Meaning you can’t even get into the country, whether you are an expat or just a tourist.
Do you research very well and everything will be definitely ok. Just be prepared while you’re hopping around from country to country. It’s not that easy to go without any basic understanding of the location you are going to or without the right papers and documents.