​Knowing when your make-up product has reached the end of its life is not as easy as knowing when your fave cheese has gone bad (that icky smell, ugh!). Each make-up product ages differently and using an expired product could result in breakouts or skin allergies.

This is your guide to how long beauty products lasts, and know when it's time to let them go!

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Lipstick: This is the longest-lasting product in the make-up bag because it doesn't spoil easily as lipsticks don't contain any water. But since they're exposed daily (or sometimes multiple times a day), ideally lip products should be replaced after a year. To tell whether a lipstick or a lip gloss has gone bad, look out for change in texture. Lip products contain oily ingredients that start to smell over time, and if they don't glide easily or the pigment doesn't spread properly, it's time to bid goodbye!

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Eyeshadow: Pretty shadows have the power of enhancing your eyes, but use an expired product and it can turn into an eye-irritant! Powder shadows have a long shelf life (they can last up to two years) but it's wise to replace them after a year if you use them frequently. But beware of cream-based shadows as they have the tendency of growing bacteria more quickly than their powdery counterparts. The best way to prolong a product's life is by keeping the tools clean, and if you use your fingers to apply, wash your hands before doing so.

Eyeliner: Like eyeshadows, liners are applied near a sensitive area, and hence, should be replaced every three months. Liquid or pencil, these eye definers can pick up bacteria quickly. If you used an expired product, you can experience itchiness or redness. Pencil liners last a wee bit longer than liquid ones, but you know they're dead if you notice a white film develop on the tip.

Foundation: What do bacteria love? Anything with water in it! And since foundations are generally water based, you must part with it within six to eight months of opening it. Although, an unopened foundation can last a while, but once the seal is broken, it's best to replace it within a year's time max!

Face Powder: Since powder-based products last a while, face powders too can be used for up to two years. However, some formulas do contain small amounts of water from certain botanical extracts and have the risk of growing bacteria. Look out for the ingredients at the back and toss the product out of your make-up bag in case it starts to smell funny or causes irritation on application.

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Concealer: This product is meant to cover up spots not cause acne, which would totes happen if the product is too old! Its biggest tell is the colour shift. Like other products, powder ones last up to two years, while liquid concealers should be tossed after a year or so.

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Mascara: This is one product you should be extremely cautious about. Mascaras pick up bacteria quite quickly as the wand is taken out for application and put back in the tube. Ideally, mascara should be tossed out every two to three months. Also as a general rule, don't share the mascara with anyone. If the product starts to smell like gasoline, it's time to throw it away.

Blush: Just like face powders, a powder blush lasts a while as it contains no water. And cream blushes should be after eight to 12 months. To prolong the life of the product, keep your blush brush regularly.

Nail Polish: If the lacquer is gooey or the colour has separated into layers and doesn't blend after shaking, it's time to move on! Pro tip: if you love the colour and must use it, put a few drops of thinner in the bottle and shake well, this will increase the longevity of the polish!

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