There is no single sealing schedule that applies to every natural stone. How often a surface needs to be resealed depends on the stone, its porosity, the type of sealer, the finish and how heavily the area is used.
Kitchen countertops, showers, mudrooms and other surfaces exposed to water, oils or contaminants should be checked periodically for absorption. If the stone begins darkening quickly when exposed to water, it may be time to reseal.
Dense materials such as many granites and quartzites may require sealing far less often than more porous stones such as limestone or travertine. Rather than sealing automatically every two years, we recommend assessing the actual condition of the stone and resealing when needed.