You know you need to take care of your skin and wear sunscreen every day, even when it’s cloudy. (Need motivation? Take our #SPF365 pledge and enter to win a $2,500 Visa gift card.) But how often do you need to do a mole check to look for melanoma?

“It’s really important to closely monitor your own moles,” says RealSelf employee Sarah. She knows more than most people will ever need to about moles. Earlier this year, Sarah was diagnosed with melanoma, the most dangerous form of skin cancer, according to the Skin Cancer Foundation.

Sarah grew up in Southern California and much of her youth was spent on the beach or at the pool. That combined with a fair complexion and a family history of skin cancer meant she was on high alert and kept a close eye on her skin.

“You need to let your dermatologist know what they need to pay attention to,” she said. “After a shower, just do a mole check and keep an eye on your skin for changes. Have your partner look at your back or take a picture with your camera phone.”

But how do you know what to look out for?

“I always tell my patients to use a mnemonic dermatologists call the ABCDE’s of melanoma to help determine if a mole is abnormal and needs to be evaluated sooner than later,” says New York dermatologist Dr. Michelle Henry

Mole Check: ABCDE's of Melanoma

Learning your ABCDE’s

Houston plastic surgeon Dr. Camille Cash broke down the ABCDE’s for us below: 

A stands for Asymmetry,” she said. “You want to make sure that moles are symmetrical, meaning that they look the same on each side if you drew an imaginary line dividing them into two halves.”

B stands for Border. The edges of a mole should be smooth. There should be no uneven areas or notches in the border.”

C stands for Color. Color can vary in moles. Most are a shade of brown. The important thing is that the entire mole is the same shade. Colors that can indicate melanoma are multiple shades of brown in the same mole, black, red, white, or blue.”

D stands for Diameter. A good rule of thumb is that moles should be smaller than the diameter of a pencil eraser,” said Dr. Cash. “Larger moles could indicated melanoma.”

E stands for Evolve. Moles that change in size, color, shape, or if they begin to itch or change in texture should be examined by a doctor.”

“The other helpful thing to think about is sometimes called ‘the Ugly Duckling Rule,'” says New York plastic surgeon Dr. Lara Devgan. “If a mole looks different from all the other moles on your body, or if it just strikes you as an outlier for any reason, then it is worth examining in more detail.”

Doctors on RealSelf tell us that it’s always best to ask a medical professional about getting a mole check for any concerns, and to do a regular mole patrol with your doctor or derm at least once a year as part of your overall wellness plan.