I Looked Up Every Country\x27s Currency Before My Trip (Big Mistake?)

Before my first big backpacking trip through Southeast Asia and parts of Europe, I did something that my friends still make fun of me for. I sat down with a spreadsheet and listed every country I might step foot in — including layover countries, train route stopovers, and three neighboring nations "just in case" — and I memorized their currencies. Names, symbols, ISO codes, the whole thing. Cambodia uses the riel, but they also take US dollars. Vietnam uses the dong. Laos has the kip. Thailand has the baht. Myanmar uses the kyat. Malaysia uses the ringgit. I drilled these like I was studying for an exam. My girlfriend asked me why I needed to know the currency of East Timor if we were not going anywhere near it. I told her "just in case" with a straight face. Was it a waste of time? Surprisingly, no. But not for the reason you might think. Knowing the currency codes saved me from genuinely stupid mistakes. Standing at an ATM in a foreign country, seeing a list of exchange rates, and recognizing that VND means Vietnamese dong and not some random fee was genuinely useful. I never accidentally withdrew 200,000 of the wrong currency because I knew what the letters stood for. It also made haggling easier. When you know that 50,000 Vietnamese dong is about two dollars without having to pull out your phone and calculate, you can negotiate without looking like a clueless tourist. The vendors in Hanoi definitely noticed. I got the coffee prices down to what the locals pay simply because I did not hesitate when naming numbers. But here is where my system went off the rails. I had memorized the official currency codes and symbols, but that barely scratches the surface. What matters more is understanding how people actually use money in each country. In Cambodia, everyone uses US dollars for anything over a dollar and receives change in riel. In Vietnam, some places prefer cash even in cities where credit cards are accepted. In Thailand, 7-Elevens take QR code payments that I had never heard of. My currency list did not prepare me for any of that. The other thing I missed was the informal exchange rates. Airport exchange counters, local gold shops, and street money changers all offer different rates, and none of them match what Google says. My meticulously memorized conversion calculations became useless when the actual rate was 5% off from the official one. Would I do it again? Yes. But I would spend half the time on memorization and double the time on learning how locals actually handle cash day-to-day. The currency list got me started. But the real lesson was that the list is just the beginning. These days I keep a running note with currency ISO codes for the countries I am visiting and the rough conversion formulas that actually work on the ground. And I still know East Timor uses the US dollar, so it was not entirely useless after all.