While there has been constant improvement in coatings for metals over
the years they all eventually wear away. How fast will depend on what
the item is and how often it is worn along with a host of other
environmental issues. This is true for lacquers, epoxys, urethanes,
acrylics etc and for plating as well. Rings especially take a beating
as do bracelets. So how long the coating will last is hard to say.
The paint like coatings generally fail in a less attractive fashion
than plating as they have a tendency to chip and crack which gives a
ragged appearance to the patina of wear that a piece develops.
James Binnion Metal Arts