I get this question a lot being a makeup artist, and often times I get asked mostly about mascara and foundation. The truth about makeup products is that they all have an expiration date at some point and some will last longer than others. The average length of time that foundation can last before it expires is 12-24 months and mascara, you should toss it every 3 months. However, I toss my mascara every month because I’m a MUA and its the safest way to be hygienic and I also use a new mascara wand for each client. On the back of your makeup product there should be a little tub with a lid on it and it will have a number inside of it. That number is the amount of months you have until your makeup expires. It’s important to be aware of the expiration date of your makeup. After awhile, if you’re using expired makeup it more than likely is harboring nasty, harmful bacteria that can cause infections. You’re chances of getting something like pink eye are DOUBLED when using expired cosmetics. To see how to clean your makeup so that it has a longer shelflife you can go here.

Also another thing to be conscious of is the sponge that comes in your cream foundations, powders, etc. Once this sponge is completely soiled THROW IT AWAY! I repeat THROW IT AWAY! You can ALWAYS purchase another one at a drugstore, counter, or cosmetics store such as Ulta. Putting a sponge on your face that has been used over and over again has so much bacteria in it that is causing more problems than it can possibly help cover. Cosmetic wedges and sponges should be thrown away DAILY, unless its the compact sponge that I just spoke about above. In terms of makeup brushes, they should be cleaned after each use with a brush cleanser. MAC makes an excellent brush cleaner that drys quickly, and I LIVE by the brush cleaner by Sephora. Your brushes should be DEEPLY CLEANED once a week with either baby shampoo or a brush shampoo. I use Johnson + Johnson’s Baby Shampoo in the yellow bottle! To learn how to deeply clean your makeup brushes and how to spot clean them, you can go here.

Marie Claire had a great article on how long most cosmetics last in case you couldn’t locate the little bottle on your cosmetics, which looks like this:

Expiration dates — beginning from the time you first open these products
Powders and shadows: 2 years 
Cream shadows: 12 to 18 months 
Foundation: 1 year 
Lipstick & lipliner: 1 year 
Mascara & eyeliners: 3 months 
Makeup brushes: Clean weekly using a mild detergent 
Makeup sponges: Replace weekly, or when sponge becomes soiled 

Tips for keeping your skin clean and your makeup fresh
— Smell your cosmetics; if they have an unusual odor, they may contain bacteria and should be discarded. 
— Always make sure that products are closed tight and stored out of sunlight, as this can destroy the preservatives. 
— Don’t use any eye products if you currently have an eye infection. 
— Never add any liquids to products unless directed by the manufacturer. 
— If there are any changes in color and texture, dispose of the product immediately. 
— Avoid sampling makeup at department stores when possible. If you do test, never apply directly from the makeup. Instead, use a clean, disposable applicator (i.e., cotton swab, sponge) to apply cosmetics, or simply ask for assistance.