At the end of the summer, do you end up with several tubes of sunscreen lotion, a few cans of sunscreen spray, and even a container or two of those sunscreen sticks?
Sunscreen - Use It or Lose It
Not applying enough sunscreen before your kids go outside in the sun is another reason to end up with extra sunscreen tubes and cans at the end of the year.
If you apply sunscreen properly, using the recommended palm-sized handful or so of sunscreen for your child's body, then a typical 8oz bottle should only last a few days to a week per child if he is outside regularly and you reapply sunscreen every few hours. Since larger kids have larger hands, that helps you adjust the amount for different-size kids. Teens and adults should use about an ounce of sunscreen each time they apply it to their own bodies.
A bottle of sunscreen that lasts all season, when your kids are outside every day, isn't getting used enough. And if you aren't applying enough sunscreen, then you aren't getting the sunscreen's full SPF protection from sun burns.
Sunscreen Expiration Dates
Unfortunately, sunscreen doesn't last forever -- it does have an expiration date -- so you do have to use it or lose it. Since it has likely started to lose its effectiveness, throw out sunscreen that is past its expiration date, which should be printed on the sunscreen container.
If the sunscreen doesn't have an expiration date, then you should assume that it has expired after about three years.
Keep in mind that if your sunscreen has been exposed to high temperatures, like if you regularly left it in the car on hot days, then it likely won't even last to the expiration date.
If the texture of the sunscreen seems to have changed, for example, it seems more gritty than it should, then you likely shouldn't use it either, even if it hasn't reached its expiration date.
Healthy Skin - Use It or Lose It
The 'Use It or Lose It' recommendation can also apply your child's healthy skin: If you don't regularly use sunscreen properly, your child may not have healthy skin when he grows up and may have an increased risk of skin cancer.
CDC. Skin Cancer Prevention. http://www.cdc.gov/cancer/skin/basic_info/prevention.htm. Accessed May 2011.