Sterling silver is a precious metal and will tarnish over time, to keep your Sederhana Jewellery tarnish free I recommend you use a silver cloth regularly to remove dirt and oils from your body. I would recommended avoiding using silver dips and liquid cleaners as they can be quite harmful to the jewellery and can reduce the longevity of it.
For the 18k Gold-plated pieces, you can also polish them with a silver cloth to keep them shiny. If possible, try not to wear the items in water (showering etc) as this will cause the gold plating to fade faster.
The 18k Gold Plating that Sederhana uses is extra thick, this helps to increase the longevity of the Gold on your piece, however, the better care you take, the longer it will last.
Additionally, do your best to avoid your jewellery coming into contact with harsh household chemicals, as this can damage and wear the items down. These include bleach, perfume, deodorant, chlorine, ammonia. I strongly recommend you take your jewellery off when going swimming as the chlorine in the pools can be hugely damaging to sterling silver and 18k gold.
If you have any questions on the care of your jewellery, please get in touch.