Whether you have marble, granite, limestone or slate it is not immune to wear and tear. It's only a matter of time before the stone begins to deteriorate and lose its natural finish. However the customer can follow a few simple guidelines in caring for the stone that will extend the time in between refinishing.
Following these guidelines will help to keep your stone looking new and stain free. A simple neutral soap such as Palmolive mixed with warm water and applied with a cotton string mop is all that is needed to keep the stone's surface clean. A properly sealed floor or counter top will be able to resist harmful liquids long enough for you to clean them up. Eventually though, if left to sit, harmful spills will penetrate the surface and leave a stain, even on newly sealed stone. It's the sealer however that gives you a chance to clean up a spill before any damage is done.
Here is a test that you can do to see if your stone is properly sealed.
Does the water darken the stone? Is it puddling or beading on the surface?
Any puddling/darkening means the liquid has begun to penetrate the surface.

* Fact: Even when newly installed, granite, marble, limestone and travertine should all be properly sealed using a high grade silicone impregnator. Factory sealers just don't cut it!