A problem a lot of us face is not knowing when we should throw out our makeup and skincare products. How long is your foundation or serum okay to use? When is it time to toss them out and replenish? Not only is using an expired product less effective, it can also be causing damage.

Decomposition of important ingredients is common in old products and the separation of chemicals can cause a lot of problems. To name a few, irritation, skin infection or worse: they can carry a virus. Three things to look for if you think you have a product that is going bad; 1) If there is any change in the color or texture. 2) If the product starts to have a strong or different odor. 3) If the ingredients begin to separate, making the liquid and solids visible.

Here our 4 common products we use and when we should replace them.

1. Sunscreen, the most important part of your skincare routine. With a shelf life of 2 years, SPF is one of the longer lasting products we use on a daily basis. However, if you leave your sunscreen out in the sun after applying it, the ingredients can separate and change the consistency of the product. If your SPF starts to turn a different shade or smell bad, or if the lotion starts to separate, it’s time for a new bottle.

2. Serums, our power house products. Unfortunately, serums do not last as long as we’d like them to. Going bad around the year mark, the active ingredients in serums loose potency and become unstable. Always check for changes in color or smell when using an opened bottled of serum.

3. Foundation, everyone’s favorite. Liquid, bottled foundation will last up to a year. If you use a cream-based foundation that you re-dip your fingers or an applicator into, its shelf life is a quick six months. This short time is due to the product being easier to become contaminated with bacteria or yeast, even with acne causing bacteria! Throw it out if there are any changes in color or consistency. Another thing to watch out for is the oil not mixing into the rest of the ingredients or not absorbing into your skin after application.

4. Mascara- the must-have eye makeup. If you use this every day, which most of us do, your mascara only lasts for 3-6 months! Not so much the ingredients being the problem, but the application. Double-dipping the applicator wand over and over and applying the product close to a mucus membrane, leaves the tube vulnerable to breeding bacteria and yeast. If your mascara beings to get thick and clumpy or starts to smell- you need to trash it and get a new one! NEVER reuse the mascara or wand that was applied while you had pink-eye.