In countries that use QFE rather than QNH (such as China), how often will a pilot set the QFE setting on their altimeter during flight? Is it only when they intend to land at an airfield, or does it get set for the nearest airfield/aerodrome and updated when entering a new airfields's airspace?
I understand that in the US, QFE is primarily used for airshows and aerobatic competitions, which are presumably operating out of a single airfield and therefore wouldn't be changed in flight.