Expiration dates on beauty products and when you should really toss them.

In writing this post because someone on my Facebook asked if makeup expires. The asker received a variety of responses from "You should throw everything away every three months!" (!!!) to "I'm still using five-year-old sunscreen!". These are both extremes and the truth is a gray area in between.

The following are my guidelines and are purely opinion, based on years of loving and collecting makeup, perfume, nail polish and other beauty products. They are not scientific (lipstickology isn't a real science, folks) and shouldn't be substituted for advice from a medical professional.

Skincare

• Sunscreen- please heed expiration dates on something as important as SPF. It helps prevent skin cancer!! 
• Cleanser- toss it if it smells funny, but I've found most cleansers to last a very long time. I've been using the same Philosophy Purity cleanser for over two years and no issues.
• Toner- same as cleanser.
• Cream/lotion in a pump dispenser- the pump dispenser prevents contamination from fingers, I would say that you're safe for at least a year from opening. If the product starts to separate, or smell "off" in any way, it's time to replace it. If the product contains SPF and you use it as your source of sun protection, please follow the SPF guideline.
• Serums (vitamins, hyaluronic acid, etc)-vary by ingredients. Vitamin C can come in many forms (Ascorbic acid and L-Ascorbic acid are the least stable and you should follow the packaging guidelines, or if you're DIYing, toss as soon as you see the product yellowing- that's oxidation, meaning the antioxidant properties are breaking down. Magnesium and sodium ascorbyl phosphate and ascorbyl glucoside are more stable forms of Vit. C and it's best to just follow packaging guidelines). With other serums, go with the smell/texture test. 
• Creams/lotions in jar packaging- use these up or toss within 6 months. Every time you stick (even clean) fingers in jar packaging, you're contaminating the product (and exposing it to oxygen). I don't even recommend using products in a jar, but sometimes it's unavoidable. You can always decant the product into a more sanitary or smaller package (I reuse tiny Clinique and Estee Lauder GWP containers- just clean them well) with a clean spatula and stretch the shelf life a bit. 
• Beauty oils, like argan and maracuja- they all have different shelf lives and you can definitely tell with your nose. New argan oil should have a slightly nutty, neutral aroma. When it's turned, it smells like old cooking oil. Smell them when you buy them. As long as you didn't buy old oils, you're safe until they've changed significantly in scent (sometimes they'll get thicker when they've turned as well).
• Rx treatments like Retin A- follow the expiration dates on the packaging.

Makeup

• Foundation/BB or CC Cream/tinted moisturizer/liquid concealer- these are generally safe to use until they separate, smell bad or oxidize (oxidation will cause them to turn darker or orange). If there's an expiration date on the package, it's usually indicating that the SPF in the product has expired. If you use foundation as your source of sunscreen (please don't if you spend more than 20 minutes outside a day), you'll need to replace when the product expires. Otherwise, if the product smells right and hasn't changed in texture, you're okay.
• Powder products including powder or mineral foundation, setting or finishing powder, eyeshadow, blush and eyebrow powder do not expire (the SPF in them does, though). You can use these indefinitely. If the top of a pressed powder product forms a hard layer, scrape that layer off (and clean your brushes!) and your powder should still be good underneath. 
• Pencils (eyeliner, lipliner, brow)- they last years, typically. Just sharpen and if the product hasn't become dry and crumbly, you're safe to use them until the pencil is used up.
• Cream eyeshadow, blush, rouge, gel eyeliner, concealer in a pot- safe to use until the product dries out. If you feel the need to sanitize, pour some 70%+ rubbing alcohol on them, let it sit for a minute, pour alcohol off and let the rest evaporate. 
• Lipstick- if it becomes hard/dry/waxy in texture or starts to smell different (sometimes like crayons), it's probably time to let it go. Continuing to use it won't hurt you, but it's kind of gross (not judging, though, I know what it feels like to have your favorite discontinued!).
• Wand products like some concealers, eye primers, lip glosses- I'm more careful about products used on and around the eyes than I am with lips. If the product changes consistency (lip gloss goes gritty or starts to smell off) I usually toss. One of my eye primers separates if I don't use it frequently, but after a bit of kneading the tube, the consistency goes back to normal and texture isn't any different from when I opened it, so I'll use it and toss after about a year from opening. On the other hand, I had a Chanel Glossimer that I used for 6 years before it developed a smell (sort of a chemical, plastic odor), so I used it until then.
• Mascara and liquid eyeliner- these are products used close to the eye and I don't believe in risking it. I'm also pretty cheap, so I don't exactly adhere to the three month rule experts suggest, but I usually toss at 6 months. If you are prone to conjunctivitis, styes or have sensitive eyes, stick with the three month rule! 
• Brushes/sponges/applicators- technically not makeup, but still an important product to address. I've noticed that many who aren't makeup junkies (and some who are!) like myself don't wash their tools! Sponges and brushes are breeding grounds for bacteria. The sponge that comes with powders and powder foundations (and especially cream compact foundations!) needs to be replaced regularly! Don't use it for the entire life of the product! You can get replacement sponges from Sephora or any place makeup is sold really. And brushes collect dead skin cells and oils. Wash them at least once a month if you use them for powder products and at least once a week if you use them for cream or liquids. Next time I wash mine I'll post a tutorial.

Fragrance

• Just use your nose. I have some that have turned after a few years and some that are still going strong after 15+ years. Store them away from heat and light and they SHOULD last a good amount of time. 

Nail Polish

• If it isn't completely dried up, it's still good. Even almost completely dried up, sludgy stuff can be revived with THINNER (NOT ACETONE-EVER!!). If you've thinned your nail polish with acetone in the past, it will eventually change color and texture and be ruined. Thinner is cheap at Sally Beauty Supply. If you care about your polish, go buy some now!

I realize this is a long post (I have put a lot of years into creating collections that I love) but I hope it's been helpful for someone. There is a lot of misinformation out there about expiration dates, and a lot of it is because the manufacturer simply wants you to believe that your eyeshadow palette "expires" so you'll buy a new one. Then there are some expiration dates you should totally pay attention to. It's important to know the difference.