We often hear about the things we should do for our skin, but what about the things we shouldn't do? Is it possible that you've developed some bad habits that you didn't even know were bad?

As part of their day-to-day fact-finding, beauty bloggers get to try just about every beauty product out there. They also attend countless seminars with top dermatologists and cosmetic formulators, so I figured these beauty gurus were the perfect people to chat with about the top beauty blunders and what you should do instead.

Using dirty brushes

"Oil and dirt residue on your brushes will alter the formula and color of your makeup, which can lead to a muddy application," says Shana King, a blogger, makeup artist and the beauty director of Anisa International, the beauty industry's leading global cosmetic brush company. "Also, the bacteria and dead skin cells found on dirty brushes can lead to breakouts and even rashes."

Her advice? Rinse the bristles of your brushes at least every one to two weeks with lukewarm water and a mild face cleanser, baby shampoo or soap. Be careful not to submerge the entire brush in water, as this can loosen the glue that holds the bristles in place.

If you use natural bristle cosmetic brushes (vs. nylon bristle), King recommends adding a small amount of conditioner every other wash. "Rinse the bristles in the palm of your hand until the water is clear," she says. "Reshape and air-dry flat overnight."

In a hurry? King says that a fast way to clean your makeup brushes is with a high-quality cleanser like Japonesque Professional Parian Spirit Brush Cleaner ($12), available at Ulta.

Not exfoliating

Paula Wade is publisher of the popular beauty blog Older Girl Beauty, which focuses on beauty advice for the 40-plus crowd. It troubles her that many people don't exfoliate their skin simply to avoid the extra step.

"The worst thing for your skin is to not exfoliate it on a regular basis, as it will never look flawless if you don't," Wade says. "When applying your makeup on unexfoliated skin, the makeup will adhere to the dead skin, making it appear flaky and uneven in tone."

Wade's favorite exfoliant is the Mario Badescu Almond & Honey Face Scrub ($15). It contains almonds and cornmeal, which naturally buff the skin in a gentle manner, so you won't have to worry about irritating your face.

Skipping the SPF

Felicia Walker Benson, the editor-in-chief of top blog ThisThatBeauty, says that we must make using SPF a daily priority.

"I always say that if you're not going to follow my 80-step (ha, ha!) skin care routine, fine," she says. "But if you do nothing else, wear daily sunscreen. It's going to protect your skin against premature aging, lines, wrinkles, dark spots, age spots, hyperpigmentation, uneven tone and, most importantly, melanoma. Sunscreen is my beauty nonnegotiable. I wear it 365 days a year -- rain or shine."

One of Walker Benson's favorite sunscreen products is the lightweight Mario Badescu Oil Free Moisturizer SPF 30 ($26).

Picking

"Do not pick at your pimples," says Erika Katz of Bonding Over Beauty, a blog that focuses on moms of tweens. "It can leave scars."

Katz says to dry up pimples with a drying lotion like the Neutrogena Rapid Clear Acne Eliminating Spot Gel ($6.99), which is sold at Target. "But in a pinch, the salicylic acid in a halved strawberry will work," she adds.

If you have a pimple that needs covering up, use something like the Neutrogena Skin Clearing Blemish Concealer ($7.99) from Drugstore.com.

And if you have oily skin, Katz suggests avoiding harsh astringents because they'll dry out your skin and cause your oil glands to work even harder to produce oil. "I like toners with witch hazel like the Seaweed Cleansing Lotion ($15-$45) by Mario Badescu," Katz says. "Or, if you would prefer to make your own, blend together equal parts witch hazel, green tea and grapefruit juice."

Sleeping in your makeup

This last one is my own personal tip. Don't sleep with makeup on your skin. Most of you will read this and say, "Duh!" but I had to mention it because even though we know it's not good for our skin, many of us do it. Bottom line is this: In addition to making your skin look dull, sleeping in your makeup will cause clogged pores, which can lead to blackheads and blemishes.

If you've been out partying all night and can't muster the energy to actually wash your face before you hit the pillow, use a cleansing cloth, like the Bear Naked Wipes ($12) from Josie Maran. These soft, biodegradable wipes will remove your makeup and the grime from the day with the help of aloe, chamomile, cucumber and vitamin E. They're also great for travel.