Holding onto that beloved mascara or trusty make-up brush? You might want to think again. While it’s tempting to stretch the lifespan of our favourite beauty products, it turns out that clinging onto expired make-up can be detrimental to our skin.

Amish Patel, a qualified aesthetic practitioner and founder of Intrigue Cosmetic Clinic, says decluttering your make-up bag is crucial for maintaining healthy skin. “When using out-of-date products, quite often these products can break down. They can have toxic chemicals in them, and when those break down, they can cause irritation to the skin, along with dermatitis and allergic reactions,” reveals Patel.

“Sometimes products can separate, too, meaning the oils will separate from the rest of the ingredients […] which can lead to clogged pores and acne breakouts,” he adds. Not what you want.

So, naturally, we wanted to pin down the lifespans of all our favourite products, from foundation to mascara, and give our skin the best chance going forward.

Charlene Flanagan, professional make-up artist and co-founder of Ella & Jo, echoes Patel’s sentiment, telling The Independent that taking care of your make-up products and tools is just as important as a skincare routine. Having worked as an MUA for more than 10 years, she got granular about how often we should be replacing our make-up arsenal and shared her expertise, product by product. Keep scrolling to find out more.

“Mascara needs to be swapped every three months,” says Flanagan. “This is a big one, as mascara is a breeding ground for bacteria, which can lead to eye infections.

Her top tip? “If it starts to dry out or smell different, it’s time to replace it. It goes without saying, but never share your mascara with anyone else.”

Adding his experiences, Patel informed us that “generally, we find that mascara liquid will start to thicken after about three to six months. “If you don’t replace mascaras,” he added, “they are going to start clogging up the pores in your eyelids, which can lead to symptoms such as styes.”

If you’re taking this as your sign to upgrade your lash stash, we’d be looking to Milk Makeup’s kush mascara (£26, Cultbeauty.co.uk), which our beauty writer had nothing but praise for. It “somehow gets underneath the lashes in a way that reaches both the top of the lash line and encapsulates the hairs”, said our reviewer.

When it comes to beauty tools, Patel describes how the lifespan of “make-up brushes depends on whether you’re going to use natural-hair or synthetic brushes – which do tend to last a little bit longer.” He added that synthetic brushes are “generally less porous, so, when you’re using make-up, it’s not being absorbed by the fibres so much and they do last a bit longer”.

Overall, “Make-up brushes tend to be good for two to three years before you should change them,” says Patel. Again, he clarifies, it depends on synthetic versus natural-hair brushes, as well as how well you look after them. You should “deep clean your make-up brushes weekly”, according to Flanagan.

“For daily antibacterial cleaning, Ella & Jo’s squeaky clean brush cleanser [£20, Amazon.co.uk] is a game-changer – just spritz, swirl on a tissue, and you’re good to go. No water needed, no downtime.”

If your brushes have given up the ghost, our beauty writer Lucy looks to Bh Cosmetics’s crystal quartz set (£28, Revolutionbeauty.com), which she describes as high-performing and, all-importantly, “soft and fluffy.”

For Flanagan, “Liquid formulas should be replaced every six to 12 months, while powders can last up to two years. Always check for changes in texture or smells.”

Patel agrees, qualifying that a foundation’s lifespan “often depends if it’s in a bottle or a tub. It can start to harden, thicken and separate, and, as it becomes thicker, it can clog up our skin”.

We’ve all been guilty of scraping the last precious drops from our foundation tube or bottle, but now’s the time to level up. Make-up expert Sabine Wiesel says Lancôme’s teint idol ultra wear (£30.75, Boots.com) is the way to go. She described it as “an exceptional formula for any skin type looking for a more polished look” in her IndyBest guide to the best foundations.

For lipstick-lovers, Flanagan’s advice is clear: “You should replace it between 12-18 months, and for lip gloss it’s every six to 12 months. If the texture changes or it smells off, say goodbye.”

If you’re looking to restock, lip gloss aficionado Ella Duggan recommended reaching for Refy’s (£16, Refybeauty.com) in her guide to her favourite formulas. We’re also fans of Fenty’s lip paint (£20.40, Boots.com).

With a changeover frequency that might shock you the most of all those mentioned here, Flanagan confided that you should “swap out your beauty blender every three months – or sooner”.

She also stressed that we need to “wash them regularly, but once they start to tear or hold onto the product even after washing, it’s time for a new one”.

Our suggestions? You can’t go wrong with the OG beauty blender (£17.50, Amazon.co.uk) or, if you’re on a tighter budget, Real Techniques’s miracle complexion sponge (£4.74, Amazon.co.uk).

Read more: The best BB creams, reviewed

“Liquid formulas should be replaced every six to 12 months, while stick formulas last up to 18 months,” says Flanagan.

When reviewing the best concealers, make-up maestro Sidra Imtiaz praised Nars’s cult creamy concealer (£20.25, Boots.com) for its “brightening quality that makes a visible difference, without merely heavily masking imperfections”. Meanwhile, looking at stick formulas, it was Merit’s minimalist perfecting complexion stick (£34, Sephora.co.uk) that impressed most, with Imtiaz describing it as “a perfect product for the low-maintenance among us”.

Eyeliners, Flanagan brings to light, are more cost-effective in one form versus another. “Pencil liners can last up to two years, if sharpened regularly, while liquid or gel liners should be replaced every three to six months, to prevent irritation.”

So, Victoria Beckham Beauty’s satin kajal liner longwear waterproof eyeliner (£32, Victoriabeckhambeauty.com) could be a good option, especially as it was beauty editor Louise Whitbread’s pick of the best eyeliners.

“These products can last up to two years, but always check for changes in texture or performance,” says Flanagan, referring to the same scent and thickness changes discussed above.

If you’re looking to top up, it was Guerlain’s terracotta blush (£38.70, Boots.com) that our IndyBest tester dubbed the best powder formula, while Benefit’s hoola matte powder (£24.75, Boots.com) stole the show in the bronzer category.

Who could forget the trusty old make-up bag? A lot of people, suggests Patel. “People often don’t clean out their make-up bags,” he explains, but everyone should “clean their bag with a disinfecting wipe – turn the bag inside out and clean both the inside and outside surfaces”. After all, when it comes to keeping our make-up setup hygienic, no stone should be left unturned.

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