Here Julia talks about caring for your natural stone counter tops. It is crucial to seal a marble or travertine top at least every 6 months. Unless it is in a bathroom that gets more use, she recommends quarterly. She plugs a couple different products to try out one including Granite Gold. They have a daily cleaner, a weekly polisher and also a sealer. Other products you can buy off the shelf in your local hardware store. They should specify for what material you are needing to seal or clean. Just check the label.