how often to apply sunscreen

You should apply sunscreen every two hours when you are outdoors, regardless of the SPF level. This is to maintain effective protection against UV rays, as sunscreen can wear off due to sweat, water exposure, or rubbing from clothing. In situations where you are swimming, sweating, or towel drying, you may need to reapply more frequently, approximately every 40 to 80 minutes, depending on the product's water resistance. If you are indoors and away from windows, reapplication is not typically necessary. However, if you are near windows or in a place where sunlight comes through glass, reapply every four to six hours. Always apply enough sunscreen—about one ounce (a shot glass amount) for your entire body during each application. Overall, the key is consistent, generous application to ensure continuous protection throughout the day.