Similar to a leather jacket, marble can last for life if taken care of properly. The two biggest dangers for your piece of marble are :

  • The violent shocks against a hard surface that could break it or chip it,
  • The etching caused by acid products :

Marble is composed of calcium carbonate that acids can eat away slowly, creating dull /rough spots known as etches. Any splash of fruit juices, sodas or other acidic products may leave a subtle mark if not quickly wiped off.

So the biggest danger for your wrist rest is food, drinks and cleaning products, so please, be cautious !
Don’t forget that it could also be the case with some skin cream, essential oils, perfume that you have on your palm/wrist.
Concerning the human sweat/natural oil, it has only a PH between 4.5 to 7, and it would not damage the marble.

Your wrist rest received a protective coating/sealing, but it only improves its resistance.

At worst, if etches are appearing, those can still be removed by using a soft cloth and some marble polishing powder, then for a shiny surface you can apply some wax.