I have thought about this. I am a younger retired expat, so mobility is not an issue, at this stage. Boarder runs are no problem. One boarder run would be the Singapore F1, which I go to anyway. Another boarder run would be to Pattaya to visit friends. I would look for a festival, sporting event, concert etc and turn that into a boarder run. Eg. Asia Cup football, World Cup qualifiers, MotoGP Buriram etc. I'm sure I would be able to line up a boarder run to coincide with something of interest. I have a couple of ex Thailand friends in Vietnam. They have told me Vietnam does not have the "back to back" visa rule like Thailand does. So, you can live in Vietnam on tourist visas, at this stage. If they were to pull the rug on back to back visas, I would look at how long they require you to be outside for, and then make a plan. It could be 3 months Vietnam, 1 month Thailand, then back to Vietnam for 3 months, and so on, for example. Can you imagine what would happen to Thailand if / when Vietnam introduce a retirement visa similar to Thailand? The condo market would crash here. Thailand would practically lose a whole generation of retiree moving here. Existing retirees would not be replaced.