Most importantly, your countertops have been sealed 1-2 times prior to completing your project. However, some stone may require additional applications down the road. Each type of stone differs in its porosity and how often it needs to be resealed (length of time will also vary depending upon the cleaners you use on your countertops). If your counters darken when they get wet, you know that it is time to reseal your counters. Resealing is a fairly simple wipe-on, wipe-off process and nothing to be concerned about.