Rest assured that your Kylie Jenner Lip Kit is safe for the next year or two. Typically, lip colors and glosses have a shelf life of 18 to 24 months, but that can vary depending on how well the pigments and oils hold up. If you notice a weird smell or a change in color, toss the product.
Foundation can last anywhere from six months to a year, provided that contact with the neck of the bottle is minimal to prevent germs from getting into the formula. Concealer also has a shelf life spanning anywhere from a year to 18 months, but again, keep your brushes or sponges clean so that bacteria won't cause the color to change, and if you use your fingers to blend it on, wash your hands prior to application.
Powder-based products should be fine anywhere from 2 to 3 years as long as the color hasn't faded and your makeup tools are (for the most part) clean. Their cream counterparts are also in for a pretty long haul, with a lifespan of roughly a year, though you'll want to throw them out if they start to dry up or the texture changes.
Since products like mascara, liner, and shadows are concentrated around your ever-so-sensitive eye area, you'll want pay closer attention to changes in these formulas to avoid getting an infection. Your mascaras and liquid liners should last up to a year, provided that they don't dry out or get clumpy before then, but if your mascara isn't kept in a cool, dry place for storage, replace it every 3 to 6 months. Both powder eye shadows and eyeliner pencils can last up to two years, though cream formulas lose moisture much quicker and may need to be tossed after six months. Gel liners are the most precious of the bunch, and tend to dry out on their own after 2 to 4 months.
Considering that nail polish should last around a year or even two if you're careful, the lacquer you picked up back in March should be fine. To be on the safe side, take a peek at the bottle to see if the color has faded or if the consistency has changed.
The shelf life of your skin care can vary depending on whether it's housed in a jar or bottle, with the latter lasting around a year. Products in jars can be slightly more complicated if you use your fingers to scoop out the cream, as this can introduce bacteria to the formula, so extend the typical lifespan of 6 to 9 months by using the tiny spatula often included with your moisturizer. As for your cleansers, toners, and serums, they should be good anywhere from 6 months to a year.
Your lotions, body washes, and shampoos should last up to 2 to 3 years, as the ingredients combined with the preservatives used in the formulas tend to be stable, even if you leave them in the shower.
With the lifespan of anywhere from 2 years to an entire decade, your signature scent is the longest-lasting of your stash, but when the fragrance goes bad, it goes bad—and that's putting it lightly. To prevent the molecules in your perfume from breaking down, store your bottles in a cool, dark area like a shelf or cabinet where direct sunlight won't hit.