How often should I reapply this lip balm for it to be effective throughout a dry winter day?

Reapplication frequency isn't fixed; it depends on your environment, activity level, and personal lip condition. The balm is designed for practical, easy reapplication throughout the day. As a general guideline: apply once in the morning as a preventive layer before heading out. If you're in a consistently harsh environment—like outdoors in cold wind, on a ski slope, or in a flight with very dry air—you may need to reapply every 1-2 hours to maintain the protective coating. In a typical office with air conditioning, every 3-4 hours might suffice. The best indicator is your own sensation. When your lips start to feel tight, slightly dry, or less smooth than they did right after application, it's time for more. Don't wait for visible flaking. The stick format makes this easy. Remember, no balm can provide 24-hour protection with a single application; its job is to reduce moisture loss and improve comfort, which requires replenishment as it wears off through talking, eating, and drinking. For overnight, a thicker application can work as a intensive treatment.