Although all cosmetics come with a “best before” date, a study by Debenhams, a London based retailer, found that 89 percent of women did not know that this information was available on beauty products’ labels. And more than two-thirds of women only change products when they run out of stock, even if it means exceeding the “best before” date, the study says.

According to the report, discolored or smelly lipsticks, mascara and eye pencils can accumulate dangerous bacteria on the skin and lead to a skin problem. Ruth Attridge of Debenhams says, “Women don’t like throwing things away but you have to remember it is probably no longer doing its job properly and could well give you a nasty infection.”