With proper care, cups should last 2 years for professional use and 5 years for home use.
After each client, clean the cups with an EPA-registered disinfectant wipe or wash them with lukewarm soapy water and rinse well. If the cup is left to stand with oil on it, it will harden. So be sure to promptly clean it after the treatment.
Do not use any mineral oil or mineral oil containing product on your cups.
Also note seasonal changes in temperature. If it’s too hot or too cold, it will affect the pliability of the cups. They will become harder in the cold and softer in the heat. To make them more pliable, place the cups in hot water. To make them harder, place them in the fridge for a few minutes.