Old makeup applicators like brushes and sponges aren't as good after a while and can actually be a health risk.
According to Grow, you can get acne or even a serious skin infection if we use them beyond a certain period. However, how often you replace brushes really depends on what type they are.
There are natural variants, which can last several years but are more pricy, and the synthetic types, which can last up to a year.
If you notice your brushes clumping together or getting stiff and the smells differently, you should probably replace them.
To make your brushes last a bit longer, Women's Health recommends washing them regularly with baby shampoo.
It's recommended you throw out beauty sponges every three months. Cosmopolitan recommends washing them with soap until most of the stains are removed once a week or so.
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