Just like food goes bad, so does your makeup. This unfortunately is not widely known. As a makeup artist and the founder of a global beauty brand, I believe it is important for me to share with my customers and clients when is the right time to throw out that foundation or mascara they've had lying around season after season. What's great is that there are steps you can take to ensure longevity of your products. See below for my personal tips of how to care for your makeup and when to throw it out.
Be sure to keep your makeup stored in a cool, dry place. Avoid keeping your products out on counter tops in your bathroom where it can get dry and humid from the stream of the shower or from direct sunlight through windows. This can cause your makeup to oxidize and expire faster, and no one wants that!
Do your best to avoid sharing makeup with your friends. I know it is easier said than done, especially when you are all getting ready together before a night on the town, but sharing makeup can often lead to sharing unwanted bacteria. A person's eyes are known to carry the most bacteria, so letting your girlfriend borrow your mascara and then using the same wand to apply to your own lashes, well, you get the idea. Due to the amount of bacteria on your lashes, I tell my customers and clients to try and replace their mascara as often as they would their toothbrush -- every 3 months.
Lipstick and glosses, if cared for properly, can last up to 24 months. When you start to notice that your lipstick appears cake-y and dry upon application, it's time for that lippie to be placed straight in the trash. Glosses will start to feel extra stickily and have a not-so-pleasant scent. Have it join the lippie in the trash.
Nail polishes can also last up to 24 months. A polish separating and clumping upon application is a sign it is beginning to expire. You can try using nail polish thinner to reactivate the product and gain a little more life out of it, but if that doesn't work it is time to say goodbye.
Liquid, creams and powder foundation and blushes can last up to 24 months as long as they are taken care of. A sign that your foundation or blush has expired is an uneven, streaky appearance when you apply it to your face. It is best to toss these products rather than trying to salvage them as expired foundations or blushes can cause irritation and breakouts.
Tip: Keep a black sharpie marker in your makeup bag to write the date you opened the product on the container. Most cosmetic labels have a month indicator on the back of the product for when the item expires. This will help you keep track of how long you've had the product opened and when to throw it out.