I'm making a plea for people to check their sunscreens for the expiration date. Some sunscreens, especially the chemical ones (oxybenzones, etc.) have a short shelf life. Especially in hot climates. The rule of thumb for chemical sunscreen usage in Florida is to toss anything that's been opened more than 12-16 months earlier. Better yet, ditch the chemical ones in favor of the old barrier one (zinc oxide, titanium dioxide) that stay on the skin's surface and aren't killing underwater reefs as far as we know.

This public service is brought to us by my triply-board-certified-in-skin-cancer dermatologist who's vehement about using adequate sun protection. And supported by a chemist friend in the cosmetics industry.