Managing your money while you travel is a top priority and taking a credit card with you on your gap year is definitely to be recommended; you never know when you might need one. They are handy to have in case of emergency or to pay for any large, unforeseen expenses like an urgent flight home. Sometimes it's necessary to have a credit card for things like hiring a car or making hotel/hostel reservations.
To avoid paying high interest charges on your credit card, it's wise to set up a direct debit from your bank account before you leave the UK. This will ensure that you pay your balance in full each month so you avoid paying any interest. Remember to factor-in any unplanned spending into your budget. Avoid withdrawing money from an ATM with a credit card. You will be charged a high cash advance fee and you will also be charged interest.
Prepaid travel cards are another great way of managing your finances while travelling. Travel cards such as FairFX, Caxton FX and Travelex work like credit cards but they won't allow you to go into the red. You load them with funds before you leave. However, it may be worth, as with your bank account, leaving the details and access in the hands of someone you trust so that they have the option of topping up your card if necessary while you are away. You can order your Caxton FX travel card here.