By Amelia Harnish
WHEN: Apply sunscreen at least 30 minutes before leaving home (and before you put on your bathing suit if you're headed to the beach), so the product has a chance to absorb and bind to your skin. Re-apply every two hours if you're outdoors or after any sweating or swimming.
WHERE: Everywhere (don't forget ears and the back of your neck) and glob it on thick as vanilla icing if you really want it to work.
Tip: An 8-ounce bottle of sunscreen should only yield eight full-body applications -- that's enough for just a few days in the sun. If you have a bottle left over from last summer's vacation, you're probably not using enough.