We are regularly asked if you need to bring cash to pay for things on the spot. For more exotic countries like India and Kenya this can be quite useful, but for most countries we advise you to pay by card on the spot. The number of ATMs in the world is so large that this is usually not a problem. You pay the normal exchange rate without extra transaction costs making this the simplest and most economical option. Also, you always land at large airports where these facilities are available. And if you drive a car, you will usually come across them on the way to your location.
For Norway I never carry cash with me because they always accept a credit card or debit card everywhere. The most commonly used and accepted is the credit card. If you take your debit card with you it is also advisable to check before departure if you can use it abroad.
If you are going to the warmer countries it is wise to carry small denominations of local currency or US dollars with you. If you have to give a tip, the smaller banknotes are the easiest way to do so.