One of the charges that you must find a way to avoid is the international bank fees that may be charged to you. As this is mostly standard, you may have to find one bank that will not charge you with it. That is because when you will make a total of all the charges, you may be shocked how big it could be. You can afford another month of travel in one place with those charges. So check what international bank do not have fees for ATM transactions.
You can also find a debit card that would be helpful in your transactions. One that will not impose any charges. Your bank may not impose charges but the other bank you would be withdrawing might implement them. That is why try to find the list of banks where you are going that will not charge for your ATM transactions. You can find a debit card that is for traveling that would let you avoid fees.
It is good that you will have multiple accounts so that you could be safe when you travel. There are many ways people could attack your bank account and withdraw money from your account. If you have one account then you do not have any other choice. That is why opening different accounts would make you safer. You can set the account in accordance with the way you will use it like a personal account, for traveling account, and for a savings account.