How Your Morning and Nighttime Routines Affect Your Health

What you do: Wash your face for all of 20 seconds

Why that's bad: Medicated cleansers need more contact time with your skin to be effective, says Joshua Zeichner, assistant professor of dermatology at the Mount Sinai Medical Center. For glycolic cleansers, which gently slough off dead skin cells, "the acid is inactivated by water, so you need to let it sit on your skin for a couple of minutes before you wash it off," he says. Acne-fighting salicylic acid requires at least 1 minute of leave-on time, as does benzoyl peroxide, another acne fighter.

One more thing: Letting cleanser sit on the skin for a minute or two is even more important when you're using a medicated body cleanser to fight chest or back breakouts—the skin there is thicker than the skin on your face, meaning the cleanser needs extra time to penetrate into follicles and pores.