When I find nickels and quarters in a certain area I know I am on to something. Nickels and quarters are roughly the same size as rings. Thus I know the area of the beach I am detecting is a good place to focus because if the quarters have sunk to 6'' inches then the rings are going to be found in that range as well. Plus it tells me that the area has the potential for good finds because a good detectorist is not going to pass up those signals. So when I find nickels and quarters, especially old ones, I know I need to pay attention to the area I am in and hunt there.
So when you do find these types of areas pay attention to the sand level, where you are on the beach (ie wetsand, high tide line, towel line, etc) so that you can start to identify them before you even start detecting.