Revealed: The everyday products you didn't know have an expiry date - including mascara, toothpaste, and tea bags

When it comes to products with expiry dates, things like foods, drinks and medicines are probably the first to spring to mind. But what many people don't realise is that several other items you use almost every day also have a limited lifespan. Some – such as mascaras and moisturisers – expire after a matter of months, after which point they can actually cause skin irritation and infections. Others, like batteries and motor oil, have a few years of use before they need replacing. 'As a starting point, always check the packaging and follow any use–by dates or guidance provided by the manufacturer,' Which? explained. 'But what if there's no date, or you've thrown the packaging away? While lifespans vary between products, there are some useful general guidelines for when everyday items may need replacing.' When it comes to products with expiry dates, things like foods, drinks, and medicines are probably the first to spring to mind. But what many people don't realise is that several other items you use almost every day also have a limited lifespan - including mascara1. MascaraIt's found in most make-up bags, but it turns out your mascara only has three to six months of life in it. Sara Spary, Which? senior researcher, said: 'The liquid can act as a breeding ground for bacteria – so you wouldn't want to risk painting that on your lashes.'On the pack or the tube you'll typically be able to find an open jar symbol with a number – usually 3M (three months) or 6M (six months) – which will show you how long it's safe to use.'2. Insect repellantAccording to Matt Stevens, Which? principal researcher, insect repellant has a lifespan of around three years. 'While insect–repelling ingredients such as Deet and Picaridin are stable and will last a long time, other ingredients used in the sprays don't last as long,' he explained. 'And if you're keeping your repellent for next year, make sure you store it in a cool, dry and dark place. That will give you the best chance of maximising its shelf life.'If you're still using an insect repellant that's more than three years old, don't panic. Mr Stevens added: 'Repellents are still likely to work after their expiry date, but their effectiveness will be reduced. Your best bet will be to buy a new one if yours is out of date.' 3. BatteriesBatteries tend to expire after ten to 15 years, depending on the type and manufacturer. Callum Pears, senior researcher at Which?, explained: 'Battery manufacturers typically put a production and expiry date on the box.'The Duracell Plus AA and AAA, for example, are alkaline options with a 10–year expiry date. 'If you're looking for batteries to tuck away for potential emergencies, I would recommend lithium disposable batteries over alkaline. 'These can be reliably stored for upwards of 15 years with a much lower risk of chemical leakage.' Batteries tend to expire after 10 to 15 years, depending on the type and manufacturer4. MoisturiserAccording to Which? moisturiser expires around six months after opening. 'In most cases, skincare products will display expiration dates and Period After Opening (PAO) symbols,' James Aitchison, Which? senior researcher, said.'The PAO symbol (an open jar symbol with a number next to it) indicates how long the product remains safe and effective once opened.'Past the expiration date, moisturisers can lose efficacy, Mr Aitchison explains. He added: 'The most likely result of using an expired moisturiser is that the active ingredients will lose their potency and be less effective than intended.'In the worst–case scenario, the preservatives in the product break down over time, allowing bacteria and fungi to grow.'Exposure to these microorganisms can lead to skin irritation, rashes and infections. 'This is particularly likely with products packaged in tubs where users remove product with their fingers.'5. Motor oilMotor oil tends to expire after two to five years. You'll be able to tell if it needs changing based on the colour – with fresh oil usually golden or amber, and older oil appearing dark brown. Dino Buratti, Which? senior researcher, said: 'Oil degrades over time, and using degraded oil could lead to serious problems with your car's engine. 'It could cause unnecessary wear, increase fuel consumption and reduce your engine's performance.'Eventually, your car's engine could fail, which could lead to a very large repair bill – or you may even need to replace your car.' Tea bags expire after 12 to 18 months, according to Sarah Ross, Which? food and health editor6. ToothpasteWhile most people get through toothpaste quite quickly, if you do happen to have an old lying about, it's best to bin it. According to Manca Virant, Which? senior researcher, most toothpaste expires after two years – although the shelf life becomes much shorter once it's opened. 'Expired toothpaste generally will not make you sick, but it will be much less effective at its main jobs, which are its cleaning power and ability to protect your teeth from cavities,' she reassured.'This is especially true of fluoride toothpastes, as the fluoride can become less effective over time, reducing protection against tooth decay. Products with expiry dates Insect repellent: 3 yearsMascara: 3-6 monthsBatteries: 10-15 yearsMoisturiser: 6 monthsMotor oil: 2-5 yearsToothpaste: 3-12 months after openingTea bags: 12-18 monthsBleach: 1 yearCarbon monoxide alarms: 5-10 yearsHand sanitiser: 2-3 years 'The toothpaste may also develop an 'off' taste and, depending on how it has been stored and used, could become contaminated with bacteria.'7. Tea bagsTea bags expire after 12 to 18 months, according to Sarah Ross, Which? food and health editor. She advised: 'Throw tea bags away if they become damp or mouldy, or develop a musty smell. 'The Food Standards Agency (FSA) advises against eating any food or drink containing mould, particularly for children, older people and those who are pregnant or have a weakened immune system. 'Accidentally drinking a cup made with a mouldy tea bag doesn't necessarily mean you'll become ill, but it's not worth taking the risk.' 8. BleachIf you've had a bottle of bleach gathering dust in a cupboard for over a year, it's best to replace it. 'Bleach becomes less effective over time as its active ingredients naturally break down,' explained Which? scientist Jacob Compton.'Powdered oxygen bleaches are generally more stable when kept dry, but can also deteriorate if exposed to moisture.'While expired bleach isn't necessarily toxic, its reduced potency could mean your home isn't as clean as you think it is. Mr Compton added: 'If you rely on weakened bleach to disinfect a contaminated surface, harmful bacteria or viruses may survive, potentially increasing the risk of illness.'9. Carbon monoxide alarmsAll carbon monoxide (CO) alarms have a set lifetime – usually around five to ten years. Mr Stevens said: 'After this time, the CO sensor will become less reliable, and you'll need to replace the alarm. 'When the alarm is at end of life, it will chirp to let you know, with some also displaying a code on the screen to indicate it needs to be replaced.'10. Hand sanitiserFinally, if you still have a hand sanitiser left over from the Covid-19 pandemic, it's time to bin it. Hand sanitiser expires after two two three years, according to Olivia Pratt, Which? scientist. She explained: 'Over time, the active ingredient or sanitising formula in hand sanitiser can evaporate or break down, reducing the effectiveness of its 'germ-killing' ability.'The World Health Organisation (WHO) strongly recommends that alcohol-based hand sanitisers have an alcohol concentration of at least 60% to be effective at sanitising/disinfecting.'If the concentration of active ingredient falls below the recommended concentration, then the hand sanitiser may not kill as many germs as it should, providing a false sense of security and increasing the risk of infection or illness.'