Dr$.$ Charles Thomas has been practicing dentistry for five years, and his practice has grown to the point where his tray setup system mist be changed. Dr$.$ Thomas has three treatment rooms and one hygiene room. He is willing to finance the necessary updating and would like to color$-$code his instruments, trays, and so forth. Before deciding on a system, what factors must be considered? Suggest some color$-$code combinations. What are the benefits of an office in which a color$-$coding system is effectively used?