Look up 'tipping' on wikipedia for everything you could possibly want to know. Here is a section I pulled regarding restaurant tipping in the USA:
At a restaurant
...
Tipping at buffet-style restaurants is not necessary, although some may think it is appropriate to tip a small amount (e.g., $1 per person) if a server refills their drinks or 10% if there is some table service in addition to the buffet....
So I wonder if this means that people should tip $1 per person when restaurants like Fire have a buffet? I see they wrote, "buffet style," but aren't they distinguishing the differences in tips based on the type of service. What about when the Ritz Carlton puts out a nice buffet?

This is obviously easier to do the cheaper the bill and the fatter my wallet, especially for my family of six.