About the first thing I had to teach the first timers to Vietnam was to throw away their underwear. Otherwise they were in total misery for a few weeks until they figured out their crotch and armpits were an infected mess because the cotton underwear kept those areas wet 24 hours a day breeding all sorts of rot. Belts could also cause problems too. I was one of the first to go there and had to figure it out the hard way. Sort of a tropical form of trench foot I suppose.