But be wary of moisturizers with sunscreen "built in." "SPF in moisturizer is not enough — you need to use a separate broad-spectrum SPF," Dr. Mahto says, which means it protects from both UVA and UVB rays. "As a general rule of thumb, opting for a product of at least an SPF 30 is useful for nearly all skin types. A lot of sunscreens come in a moisturizing base, so if you have normal, combination, or oily skin, you don't need to moisturize and use a sunscreen." Your nighttime routine should be just as straightforward. "Simply make sure you have cleansed properly using your acid-based cleanser, and apply your chosen retinol afterwards."