As department stores increased in number and size, retail spaces within shops were furnished in different styles as examples for customers. One particularly effective advertising tool was to set up model rooms at national and international exhibitions in showrooms for the public to see. Some of the pioneering firms in this regard were Waring & Gillow, James Shoolbred, Mintons, and Holland & Sons. These traditional high-quality furniture making firms began to play an important role as advisers to unsure middle class customers on taste and style, and began taking out contracts to design and furnish the interiors of many important buildings in Britain.