Apply liberally 15 minutes before sun exposure. Reapply at least every 2 hours. Use 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 sun, especially from 10 a.m. – 2 p.m.; wear long-sleeved shirts, pants, hats, and sunglasses. Children under 6 months: ask a doctor.