Over time the mill applied fabric protectors can loose their effectiveness. This is due to the fibers being abraded during heavy usaged. Since the biggest enemy of the protectors is abrasion from wear, it varies with each situation, the general recommendation for re-application is after each professional cleaning. Fabric protectors is an insurance for you, your upholstery will give you the same results every single time its clean. This product is recommended for people with an active house because things happened, and you can only hope to be able to cleaned them up. AquaTec uses Dupont Teflon's technology to provide more repellency than any other fabric protector. Teflon advanced delivers its protection by forming a molecular shield around each fabric fiber. It repels liquids, allowing spills to be removed before staining or wicking can occur. This product keeps dirt from sticking to the fibers, making upholstery easier to care for. Unlike other protectors, Dupont Teflon Advanced is applied, dries quickly with your fabric, and leaves no odor. It is non-toxic and safe to use around family, and pets. (solvent-free)