When you grow up as a girl, you’re aware that you’re going to reach many different milestones during the course of your life. Even just as a teen, you’ll have to get used to adapting to new things.

As kids, we loved having our hair tied back in our favorite scrunchies and jamming out to our favorite music in mismatched clothes, but then the day comes when you realize you’re not a kid anymore. That’s usually when we’re first introduced to makeup.

It’s a terrifying and thrilling experience. You may have snuck some lipstick and probably put on too much eyeshadow as face paint for a make-believe game.

Now that you’re an adult, you have a makeup bag of your own — and you know how to use it.

Although you’re good at applying it, have you thought about when to replace the makeup you rely on? At some point, you’ll have to throw out what you have and buy new stuff, but maybe if you just don’t think about it too much, it’ll never happen.

Wrong.

It’s a terrible habit.

You should be in the habit of replacing your makeup. Otherwise, you’re running the risk of getting an infection. So what if you used to use that makeup tube to prepare for job interviews back in college?

It’s not your lucky charm, and you won’t feel the same way if you swipe some on one morning and spend the afternoon at the ophthalmologist getting your swollen eyes checked out.

Have you ever tried to find out what happens when old makeup goes on your skin? Even powdered makeup can be a breeding ground for bacteria over time, so when you dab it on your face, that bacteria gets pushed into your pores and causes irritations and acne.

There’s no point in wearing old makeup if it’s only going to make your skin bad. That leads to using more makeup and the cycle repeats.

Know when to toss your makeup.

When you’re supposed to toss your makeup depends on what you’re using. Some ladies like to go all in with lotions, contouring and false eyelashes. Others swipe on mascara in the morning and they’re good to go.

Check out this list and see what you use, and then write down when you should throw items out if you know you won’t remember when the time comes.

• Mascara should be a top priority when it comes to replacing makeup. There’s too much damage that can be done to your eyes if you don’t throw it out. You should replace your mascara every three months, or four times a year to prevent bacteria from making a home inside the tube you use.
• Eyeliner is another dangerous thing to keep around for too long. It can get down in the crevasses between your eyelashes and do some real damage. It has the same shelf life of mascara, which is easy to remember. Get new eyeliner every three months and you’re good to go.
• Liquid foundation and powder foundation are about the same, too. While bacteria have an easier time making a home in the liquid foundation, they both have daily contact with your skin and should be thrown out once a year to every 18 months so your skin can stay fresh and clean.
• Lipstick is easy to forget to replace because it’s so easy to take for granted if it’s part of your daily routine. The good news is that lipstick is meant to hold up over time, so the preservatives in it won’t break down for at least a year. Once it starts getting hard, it’s time for a new one.
• Sponges are what you really need to be concerned about if you use them to apply makeup. They need to be tossed once a month, so you might even want to work out a budget for them. Thankfully, if you’re stretched for cash, you can find them pretty cheap at any drugstore.

Don’t worry about replacement costs.

Yes, makeup is expensive, but it’s priced high for a reason. Each product is thoroughly researched and put through trials so they’re safe and effective for anyone to use.

In the meantime, try to prolong the freshness of your products by looking at the care directions on the back of the package. Storing what you need in a cool, dry place will keep bacteria from spreading if you don’t know where to put your makeup bag.

Otherwise, research what you have on the brands’ websites and consult their customer service for specific questions.

You’ll find that after you learn what you need to know, taking care of your makeup will become second nature.