daily walking the dog i carry two flask type mugs ... one with tea and the other with coffee, but for years i would carry a dragon gel cooker (or hexi cooker) and cook lunch or make a brew while i was out. The biggest advantage i can see with flasks is time saved.
Hi Neil. Thanks for watching and commenting. It is a balancing act - a flask can provide immediate hot water/coffee/tea but when you have emptied the flask you need a stove if you got the timimgs wrong. Thanks for watching and commenting. ATB. Nigel