These ceramic objects are delicate. If you take care while wearing and make sure to not drop on a hard surface, your ceramic jewellery should last a very long time. When you are not wearing, store in a small box and handle with care to prevent breaking and cracking.
If travelling, make sure to protect your piece. The earrings, preferably, shall be packed separately.
The sterling silver posts, over time, develop a natural patina that many people like, but if you don't, a cleaner specifically labeled for sterling silver, will make them bright and shiny again. You can use a polishing cloth for that.