It's hard to forget, but makeup does have an expiration date. The products themselves are not required to have an expiration date on the bottle, but your makeup should not just be used until you get to the bottom. Some products do offer a bit of guidance. You might see a number and a letter that indicates how long you can use your product. For example, 12M for 12 months or 2Y for 2 years. According to Today, old makeup can lead to infections, though many go undiagnosed or unreported. Makeup past its expiration date can cause irritation, skin redness, burning sensations and skin hypersensitivity.

Here's the shelf life of your everyday beauty products.

1. Mascara

Eye makeup fittingly has the shortest shelf life. You should toss your mascara every two to three months, but if you see it get lumpy or it smells weird before that time, you should get rid of it.

2. Lipstick, Lip Gloss

Lipstick has gone bad if it's dry or extra sticky. You should be tossing the products every two years; lipgloss has a shorter shelf life of one year.

3. Powder, Eye Shadow, Blush

These powdery products have a shelf life of two years. If they get flaky and dry before that time, then it's time to toss them. A good tip for this is to regularly clean the brushes you apply these products with so that you don't spread more germs. (Seriously, there are a ton of germs hiding in your brushes.)

4. Liquid Foundation, Concealer, Sunscreen

If you are keeping your products out of the sunlight, you concealer and liquid foundation can be good for about six to 12 months. If the color has lightened or the product has separated into layers, then it is time to toss it. Sunscreen should be tossed after about six months.

5. Nail Polish

Nail polish, too, has an expiration date. It tends to go bad after about one to two years. If you shake it and it doesn't blend or if it's goopy, then your polish is bad.

6. Perfumes

Perfumes don't last forever, but the good news is that they are good for about eight to 10 years. Signs of expired perfumes include lightening or smelling different.