Show visible cultural respect
Shoes off at temples, greet elders first, learn a little Vietnamese.
Cover shoulders and knees at pagodas, remove shoes in homes and temples, and address the oldest person present first. Xin chào and cảm ơn, badly pronounced, change how you are treated within a week.
Source Community-reported
Budget honestly and count your tax days
183+ days in a year makes you a Vietnamese tax resident.
Da Nang is cheap until a visa run, insurance and a hospital bill land in the same month. Count your days as you go: cross 183 in a calendar year and Vietnam taxes you as a resident, on worldwide income.
Source Official — Vietnamese decree
Don't be the loud, entitled foreigner
Behaving like a guest is the cheapest goodwill you can buy.
Volume, haggling over pennies and raising your voice at staff all read the same way locally, and the reputation travels down your street faster than you do. Politeness is also the fastest route to a landlord who fixes things.
Source Community-reported