If you are planning any kind of outdoor activities whilst travelling, you will need head protection with hats and scarves. Mountain trekking and cold climate activities will require a thermal hat to protect your head and ears. A warm hat packs down super small and will keep you warm in blustery conditions. A balaclava will go a step further and give you great protection from cold exposure.
In hot climates, a broad rimmed hat will keep the Sun off your face and neck. Bandanas and shemagh scarves are excellent for the desert; versatile wearing options mean you can cover up as much as is needed if a sand storm kicks up. For the ultimate in versatile, high performing head and neck protection- the range by Buff are superb!