How much should I bring ?
Bringing a sufficient amount of cash with you PRIOR to arriving at your vacation destination is ALWAYS easier than tracking down a bank or other financial institution in a foreign country.
For those who live in the United States, credit card use is extremely frequent for all types of transactions, whether it's for groceries, gas, restaurants, shops, and public transportation.
This is not necessarily the case in other worldwide places. Many smaller retailers do not take credit cards or, if they do, place a service charge on top of the purchase.
Bring enough cash (both in your own currency and in whatever local currencies you might be needing) to last for your entire trip length.