I have a confession to make, I keep makeup waaaaay longer than I should. Some of it is just so expensive and the cheapskate in me just cringes to throw it out. So just how often should you be throwing out beauty and skincare products? And what can you "forget" to throw out for a few months longer?
Mascara: Mascara is the one thing I will not keep past the allotted time period, once you've had a really horrible eye infection you will be extra careful too. Mascara should be replaced every 3-6 months, but if it becomes super clumpy (which is a sign of air drying it out and bacterial growth) or starts to smell weird (bacteria!), throw it out. A tube of mascara costs less that a two week supply of antibiotics and that eye patch pirate look is so two seasons ago.
Lipstick: I will fully admit, some of my lipstick is more than a few years past the "throw is out after a year" rule, but who finishes a tube of lipstick in a year? Check for changes in texture and smell, those signal a lipstick going bad. I clean mine with alcohol every few months so I have yet to have one go bad (fingers crossed, knock on wood), so I think this is a rule you can fudge a bit. The one year rule also applies to lip liners.
Foundation: Both liquid and powder should be replaced every two years, though I think most people finish them up well before the toss by date. I do have a foundation I quit using for like a year that is now quite old and smells funny so I will be tossing it next time I remember and am in the bathroom. Remember, old makeup can be the cause of that persistent acne you've been battling.
Blush: Blush has a two year window, but so long as you store it properly and clean it with alcohol every once in a while I think you can fudge that rule a bit. If it gets really dry and crumbly (or wet, ew) or develops a smell toss it.
Eyeshadow: This also has a two year life, but I think with proper care and maintenance you can keep it longer like with blush. I know some of mine is well past the two year window and hasn't changed one bit.
Eyeliner: Both liquid and pencil should be tossed after a year of use. Pencils you can sharpen can be kept a little bit longer but do not keep liquid, cream, or gel eyeliner past that year. Germs and bacteria will hide and grow in the actual eyeliner and give you a nasty eye infection.
Face Creams/Lotions: These should be tossed after a year. They'll separate and lose their effectiveness as time goes on, and can actually exasperate the problems they are suppose to fix, like dry skin and acne.
Sponges: If you use sponges to apply your makeup they should be washed after every few used and completely replaced after 6 months. If I use wedge sponges I'll replace them every week, but something expensive like the Beauty Blender can be replaced every 6 months if you take really good care of it. Brushes should be cleaned weekly as well, but don't really need to be replaced unless they are coming apart.
This just covers the basics, but a good rule of thumb is if it changes or starts to smell toss it. What's the one makeup item you've had for so long it's embarrassing?