And what about that lipstick, the one you've been meaning to chuck out since 1999? Editing your stash is not only better for your skin's health, it will also make getting ready quicker and easier.
With recent research from MakeupBrushes.co.uk showing that the average lipstick has been used by nine different people, and mascara often being shared amongst as many as four friends too, it's more important than ever to keep your make up bag fresh and bacteria free.
Here's when you should be replacing your make up bag staples...
FoundationBag life: 6 months to 1 year after opening
If it starts to smell odd, seperate or change in colour, ditch it. Keep your fingers away from the neck of the bottle so that it stays germ-free for longer. Instead, tip onto the back of your hand before you apply.
ConcealerBag life: 1 year
When using to cover a blemish, don't touch the spot with a brush, then dip it back into the pot, as this spreads bacteria. Instead, pour the product onto the back of your hand and apply it from there. If your concealer starts to change in texture, replace it.
LipstickBag life: 12-18 months after opening
Lipsticks are more waxy than 'watery' so don't pose the biggest threat, but if you notice it becomes dry or a bit gloopy, chuck it, even if it's your favourite! Keep lipsticks in a cool, dry place and they'll last longer.
MascaraBag life: 3 months
Pumping the wand in and out (we all do it!) causes bacteria to build quickly. When it starts to flake or look clumpy, you know what to do. Plus, replacing it is so important to avoid eye infections. There are some amazing mascaras on the market for less than £5, so no excuses.
EyelinerBag life: 3 months
Like eyeshadows, liners can pick up bacteria and bring it back to your eye very easily. So if your eyes start to feel itchy, seem a bit red or in some circumstances, you develop conjunctivitis, ditch that dodgy pencil! If you regular sharpen, pencils rather than liquid eyeliners should last a bit longer.
Powder eyeshadow and blushBag life: About 2 years
The longest-lasting of all of your products, but when they become hard or chalky it's best to buy new. And be sure to clean applicators regularly to prevent germs spreading from product to face and back again.
BrushesBag life: 3 years with good care
It's a faff, yes, but a little regular maintenance wil keep your brushes bacteria-free, and prolong their lifespan too. Every few weeks wash them with a baby shampoo in warm water, then stand them in a mug and leave to air-dry.
Nail polishBag life: 2 years
Once a bottle is opened some ingredients will start to evaporate. So if you notice a thick, goopy, separated consistency where the pigments settle on the bottom, even after a good shake, toss it out.
PerfumesBag life: 3 – 5 years
Perfumes can last you years without expiring but keep them out of direct sunlight and make sure the lid is on tightly, as air can contaminate the product causing it to oxidize. And if it starts to small a bit wrong, throw it!
MoisturiserBag life: 1-2 years
If the texture of your lotions changes or it starts to small a bit 'off' before the 1 year mark, toss it. The more active ingredients it contains and the more bacteria it comes into contact with (e.g. when you dip your fingers in the pot), the less stable it will be and the more quickly it will expire.