Whether or not you wash your face day and night, you might be surprised at what's left on your skin after a single cleanse.
Environmental pollutants in the air, as well as cosmetics such as sunblock and waterproof make-up, combine daily with the skin's naturally-sticky sebum (oil) secretions to form a thick, slick, waxy coating by the middle of the day. Yuck.
If you're like most people, you only spend about 20 seconds cleansing with standard face washes or make-up removal wipes. That's not enough to penetrate those layers of debris. You're left with excess sebum, make-up, pollutants and grime that give your skin a dull, congested appearance and prevent your skin care from doing its best work. Cleansing twice with the same cleanser won't do the trick, either.