Currency and Exchange suggestions…
It is imperative when exchanging USD currency that you use pristine (like washed and ironed looking) bills. USD currency is frequently counterfeited around the world, so many banks, outside the U.S.A. only accept pristine new USD currency bills. Before my trips I go to my local bank and get large bills, $100 and $50 as those will get you the highest exchange rate in Bali, and I tell them I need them "hot off the press" because even a tiny tear, fold or crease will mean they can’t be cashed at a bank or business and are in essence worthless while traveling. Once I get the "pristine" bills from the bank teller I step aside and go through each bill carefully inspecting for ANYTHING less than pristine. I almost always find one or two, get back in line and ask the teller to exchange those unusable bills for pristine. Usually, they get the hint after they see you step aside and inspect each one carefully so the second time around, they might go back to the vault.
Alternatively, you could get your bank to do the exchange for you into local currency. My bank offers this, and they are a local bank not a nationwide bank, but I do pay a fee for that service. Of course, you'll pay a bank or authorized money changer to do that at your destination so why not save yourself the hassle and the time?
Using a local ATM is a good alternative although I highly recommend you check with your bank for verification of the amount you can collect and if there are fees. Keep in mind if using the ATM option, you want to know the amount you wish to withdraw in local currency…not in USD. This sometimes involves a lot of zeros so be extra cautious when making the withdrawal and have the amount written out for clarification.
Keep in mind if you are traveling with an emergency "stash" of USD those should be pristine bills too. If they are anything less than perfect, they are useless as no one will take them there. Please don't use those for tips. They will be accepted by the person on the receiving end to be kind, but they are worthless to them unless they meet up with an American willing to exchange them for pristine bills.