In Argentina, if you can afford to start paying an additional monthly sum to switch to OSDE (the best medical insurance in the country) you are free to switch jobs without worrying about an illness becoming a preexisting condition, because you just take your OSDE plan with you wherever you go. You only need to make sure that they will allow you to have OSDE as the "obra social" (government-mandated medical insurance for employees). You can even become self-employed and keep your OSDE plan (but in that case you have to pay about 80% more, still a bargain compared to the US). At last I could find something that works better in Argentina than in the US! Of course it's not cheap, but my plan is one the most expensive and it's under USD 350 for my wife, three kids and myself, including dental, ER, cosmetic surgeries, fertility treatments, some of the best doctors in the country and 100% coverage in neighbouring countries (one of my daughters was hospitalized when she traveled to Chile and we didn't have to pay anything at all, same with daily visits to the ER with another daughter during a two-week trip to Uruguay).