For sunscreen use: 
 
  apply generously and evenly 15 minutes before sun exposure  
   reapply at least every 2 hours  
   use a water resistant sunscreen if swimming or sweating  
    Sun Protection Measures. Spending time in the sun increases your risk of skin cancer and early skin aging. To decrease this risk, regularly use a sunscreen with a Broad Spectrum SPF value of 15 or higher and other sun protection measures including: 
   limit time in the sun, especially from 10 a.m. – 2 p.m.  
   wear long-sleeved shirts, pants, hats, and sunglasses  
   children under 6 months of age: Ask a doctor