My 20-year old ceramic (porcelain?) kitchen sink tends to grow mildew if left alone for a few days. The mildew prefers to grow in the scratch marks at the bottom of the sink.
Also, the bottom of my sink is flat, so some water tend to remain there for a long time.
Would a new sink be more immune to mildew? What about metal sink? Are there kitchen sinks made with a gentle slope at the bottom such that water would roll off but dishes can stay put?