A new survey by cosmetics brand Stowaway revealed that 80% of makeup users continue to put expired products on their face - even though they're aware it's gone off.
This is more than likely because 75% of the 4,052 women aged 25-50 who were questioned by the researchers don't use up their makeup - not just before it expires, but ever.
"The ingredients can react and change over time and old makeup can provide a breeding ground for germs, this can mean dermatitis, bumps and blemishes," she said.
"Expired makeup should really be thrown away - your face will thank you."
Not sure whether to keep it or chuck it?
Mascara: Bin after three months.
Eyeliner and eyeshadow: Has a shelf life of six to 12 months, liquid products expire faster.
Lipstick: Keep for up to 18 months.
Foundation, powder and blusher: Lasts around a year, but check the bottom of the container as there's usually a number indicating how many months it will last for after opening.
To rev up your makeup hygiene even more, make sure you clean your makeup brushes frequently - here's how often you should do it.
Can't bear to part with your limited edition MAC lippie? You can help stop germs spreading by spritzing products with an antibacterial makeup spray after use. We love Pro Hygiene Collection Antibacterial Makeup Spray, £15 from feelunique.com.