It is natural for metal jewelry to oxidize over time. To slow down this process wipe with a microfiber cloth and store in plastic zip lock bags when they are not being worn.
Do not clean plated jewelry with chemicals, instead gently wipe with a soft cloth. Remove jewelry before showering, swimming, or exercising.
Jewelry should be handled with care, excessive bending will cause the pieces to break. In order to achieve a long lifespan of your jewels, keep adjustments to a minimum.