If you pull out the same sunscreen you used last year, have you checked the expiration date? Most companies make it to last a year at a time, so your old stuff may not have the same protection it did last summer.
That advice from Dr. Mark Jaffe, a Dermatologist, who adds don't be fooled by moisturizers or cosmetics that say they include sun protection. You need more proof than that. "If it doesn't give an SPF number, it's probably got very little protection. But if it says a 15, it's got as much protection as a standard brand name. In fact, probably what it really is mostly a sunscreen just calling itself a moisturizer," says Dr. Jaffe.
For your best protection against skin cancer, Dr. Jaffe says use a sunscreen or sunblock liberally 20 minutes before you go out and re-apply every two hours or after swimming or sweating, even if the bottle says "All Day Protection.". Be sure to limit your sun exposure between 10 a.m. and 4 p.m. when the sun is strongest.