Very true, but the other half is to ensure you don’t use a card with a foreign transaction fee, which will cost you 3-4%. There are free cards like the Amazon Prime Visa that don’t have it, but that fee is very common.

The other thing I hate to see is people using the currency conversion desks at airports, or buying foreign currency from their banks in advance of trips. They give you awful rates.

Assuming you’re traveling to a civilized country, just stick your card in an ATM when you land and pull out the cash you need. Good banks don’t even charge their own ATM fee, so your total cost is the $3-4 that the ATM owner charges, and you get a pretty fair rate.