When it comes to exfoliation, less is more, cautions Laura F. Sandoval, DO, a senior clinical research fellow in the department of dermatology at Wake Forest University. "We actually tell most patients not to exfoliate, because once people start, they can get very aggressive and it can really irritate their skin," she says. This is especially true of people with sensitive skin, or who are already on a medicine, like retinol, for acne or anti-aging benefits. "Those products act as exfoliants already, so you probably don't need to do much else on top of using them and a gentle face wash. If you're not already using a prescription-strength product and you want to give exfoliation a try, try it once a week for dry skin or twice a week for oily skin, and see how your face reacts.