Licking your lips-saliva evaporates and dries out lips and irritates lip skin.
Airplane travel-air on planes is dehydrating (low humidity, high altitude).
Lipstick-ingredients can dry out lips and highlight lip creases.
Toothpaste-tartar control versions can irritate lips.
Lip balms with fragrance can irritate and dry out lips.
Hot showers-wash away protective oils.
UV Rays-protect delicate lip skin from the sun with a lip balm containing a mineral sunscreen.
Mouth-breathing-causes lip dehydration.
Indoor heat-sucks moisture out of the air and contributes to dry skin.
Medication-dry mouth can be a side effect of certain drugs, which can cause dry lips too.
Climate-dry air and high altitude can dry out your lips.