Proper Use of Sunscreen
Exposure to ultraviolet light, UVA or UVB, from sunlight accounts for 90% of the symptoms of premature skin aging such as wrinkles and skin cancers. The most important skin-care product available to prevent wrinkles and skin cancer is sunscreen, but most people do not use sunscreen correctly.
Important factors to consider with sunscreen use are the spectrum of UV radiation absorbed, the amount of sunscreen applied, and the frequency of application.