Check the Label. If cosmetics have active or prescription ingredients, some of them can degrade over time and actually change into other things that may have a different or unintended effect on your body. That is why medications and skin care products carry an expiration date. Some topicals may also grow bacteria over time and could result in unwanted infection. Best to follow the instruction on the label.
Cosmetic expire. Some products have quicker expiration dates than others. Pumps stay more clean than open jars, and the longer you use a jar, especially if it is an eye cream, you run more risk of getting an infection. You shouldn't use something usually more than a year old and even less with certain products.