The biggest enemy of gold plated jewelry is human sweat. Human sweat is different for each individual and also varies from time to time for the same person. Certain chemicals in the sweat, if left on the jewelry's surface can tarnish or "black" the jewelry at the exposed parts.
The best way to avoid this blackening from happening is to take due care after every wear. Our jewellery is washable. After every wear to be sure that there is no sweat chemicals left on the surface, wash it in soap water, use a soft brush if required and then rinse with cold water. Regular - tap water is ok. Then place it on a towel and use a simple hair blow dryer to dry it thoroughly until the towel itself becomes dry and the jewelry is quite hot to touch. Then store each piece in separate ziplocks to isolate from atmosphere.
Still if something untowards happens, not much is lost. The stone materials used in our silver jewelry are good enough to withstand repolish as many times. If you do happen to detect tarnish on your jewelry, let us know and we will get it repolished at a very reasonable price.