Recommendations are independently chosen by Reviewed’s editors. Purchases you make through our links may earn us a commission.

As you (hopefully) already know, makeup doesn’t last forever. And while almost everyone is guilty of holding on to things past the expiration date, in the case of makeup, it can lead to a dermal disaster.

Makeup doesn't always wave red flags that it's time to toss, which leads many people to continue to unknowingly use expired products and proceed to scratch their heads at their sudden onset of acne flare-ups.

The truth is that bacteria can find its way into products easier than we think, and when germ-laden powders or creams are picked up on a makeup brush, that bacteria can be applied to your skin.

‘Because expired makeup products harbour bacteria and the molecular and chemical structure of the makeup changes, these changes can cause dermatitis, which can then cause redness, rashes, skin irritation, infections, and even pink eye’, warns Savannah St.

Jean, a Florida-based makeup artist and the owner of Savannah Rae Beauty, said: ‘When you look at your makeup products, you should be able to find a little bottle or jar symbol with a number inside, which represents how many months the product is good for [after it’s opened]’.

Kidderminster Shuttle: Look for the jar on the back of your makeup packaging to know when it expires. Credit: Getty Images / Oleksandr HrutsLook for the jar on the back of your makeup packaging to know when it expires. Credit: Getty Images / Oleksandr Hruts

While the majority of products have the symbol, some do not, or they're listed on the outside packaging, which many people throw away after purchasing.

That's why you should be on the lookout for these telltale signs that indicate your products have reached the end of their lifespan to ensure you're not using expired products.

1. How often should you replace liquid foundation?

Kidderminster Shuttle: Store your foundations in a cool, dry place. Credit: Getty Images / twinsterphotoStore your foundations in a cool, dry place. Credit: Getty Images / twinsterphoto

Liquid foundations usually last 12 months after opening.

St. Jean notes that the telltale signs to look for in an expired liquid foundation are product separation, a foul smell, inconsistent texture, or an orange, oxidized colour when in the bottle.

Any of these signs can occur before the product's actual listed expiry date, depending on how it's stored and used.

To increase the shelf life of your liquid foundation, avoid touching the opening or neck of the bottle, and if it doesn't have a pump, simply pour it onto the back of your hand and dip your finger, sponge, or brush into the product from there.

Also, keep it stored in a cool, dry place away from sunlight (that means not on your windowsill)—the heat and sun could cause the oils in your foundation to separate.

Get IT Cosmetics CC+ Cream with SPF 50+ from Amazon for £42.30

2. How often should you replace powder?

Kidderminster Shuttle: Look for a hard film or changes in colour in your powder products. Credit: Getty Images / misumaLook for a hard film or changes in colour in your powder products. Credit: Getty Images / misuma

Powders, including bronzers, blushes, and face powders, typically last 12 to 18 months after first use.

‘Powder products on their own don’t harbour bacteria because those germs need some sort of moisture for growth and will eventually die on a dry surface. The dangers arise when we use a brush or sponge that has residual oils and moisture on it to pick up the powder product’, explains St. Jean.

‘This adds moisture to the dry powder product and can cause bacteria to flourish’.

This can also create a hard, darkened film, known as ‘hardpan’, that can prevent the product from sticking to the brush.

You may be tempted to scrape this off to prolong the use of your product, but it's best practice to use this as a sign it's time to toss.

In addition, make it a habit to only dip a clean, dry brush into powders to keep them bacteria-free. This means washing your brushes with a dedicated cleanser or a mild shampoo at least once a week and allowing them to dry fully before using.

If you notice texture issues or that visible film on top of the product despite your efforts, it’s time for a replacement.

Get No7 Perfect Light Loose Powder from Boots for £11

3. How often should you replace mascara?

Kidderminster Shuttle: Each time you open your tube of mascara, bacteria gets it. Credit: Getty Images / AndreyCherkasovEach time you open your tube of mascara, bacteria gets it. Credit: Getty Images / AndreyCherkasov

Mascara tubes are bacteria's living dream, as they thrive in moist, dark environments. Because it comes into contact with your eyes (and is nearly impossible to keep sterile), mascara should be replaced every three months.

Think about it: Every time you apply mascara onto your eyelashes, you also coat the wand with bacteria from your eye secretions and then re-dip into the tube, introducing new germs with each dip.

You can avoid eye infections if you know when to toss your mascara: If the formula is thicker than it was when you first bought it, it's dried out, its consistency is clumpy and flaky, or it smells off, it's time to say goodbye.

We know how tough it is parting ways with a luxury mascara that's gone bad when there's still product left in the tube, so to avoid waste, don't open more than one mascara at a time.

Get Milani Highly Rated 10-in-1 Volume Mascara from Beauty Bay for £14.25

4. How often should you replace makeup pencils?

Kidderminster Shuttle: Pay attention in colour and texture changes for your pencil products. Credit: Getty Images / Gam1983Pay attention in colour and texture changes for your pencil products. Credit: Getty Images / Gam1983

St. Jean says that products in pencil form—eyeliner and lip liner—typically expire after 18 to 24 months.

If there's a change in smell, colour, or texture (even after sharpening), or if the product has dried out, it's time to toss it.

A change in performance is also a dead giveaway—is your kohl eyeliner unable to draw a smooth line? Is your lip liner applying chunky? St. Jean says either of those are indications that it's past its prime.

To extend the life of pencil products, keep them away from moisture-rich environments, like your humid car and steamy bathroom.

Get the Zoeva Soft Kohl Eyeliner from Cult Beauty for £9

5. How often should you replace lip products?

Kidderminster Shuttle: Because you may ingest lip products unknowingly, it's important to stay on top of replacing them. Credit: Getty Images / misumaBecause you may ingest lip products unknowingly, it's important to stay on top of replacing them. Credit: Getty Images / misuma

Lipsticks and liquid lipsticks usually last 12 to 18 months, and because they can be ingested, it's essential to abide by the expiration date.

‘If it's applying really thick, has a change in taste and smell, or a change in colour, it's due to be replaced’, St. Jean says.

As for lip glosses, be attune to any change in smell. Ageing causes ingredients to break down and the product's scent may turn rancid.

If it's in a clear tube and you notice a cloudy appearance, it's time to toss. Typically, glosses last for 12 months before needing a replacement.

Get Wet n Wild MegaLast Liquid Catsuit Matte Lipstick from Amazon for £2.95

6. How often should you replace makeup sponges?

Kidderminster Shuttle: Wash your makeup sponges after each use and replace them often. Credit: Getty Images / AnastasiiaBabakovaWash your makeup sponges after each use and replace them often. Credit: Getty Images / AnastasiiaBabakova

Makeup sponges are breeding grounds for bacteria because they are typically used when damp.

‘It’s imperative that the sponge is washed after each use with anti-bacterial soap and replaced at least every three months’, advises St. Jean.

If you use a cosmetic wedge, use a new one each time you do your makeup.

Also, if your sponge has tears in it, is severely stained, or has lost its cushiony texture, it's time to replace.

Get the Beautyblender Original Makeup Applicator Sponge from Amazon for £17

The product experts at Reviewed have all your shopping needs covered. Follow Reviewed on Facebook, Twitter, and Instagram for the latest deals, product reviews, and more.

Prices were accurate at the time this article was published but may change over time.