This paper examines the contribution which Market Research can make to understanding how children and adolescents develop into adult consumers. In order to illustrate some of the methods available and findings involved, a case history is presented on the development of young peoples' attitudes towards domestic fuels. The case history involved interviewing 786 school children between 11 and 15 years, and 788 young people between 16 and 25 years. The scope of the study included: attitudes towards electricity and gas in the home; sources of influence on attitudes; ideas about setting up home, etc. The theoretical basis and methodology of studying development by age are discussed in some detail. The results of the study show that the attitudes of young people setting up their own homes are heavily influenced by earlier experiences in their parents' homes, and that thinking about fuel decisions changes when young people are confronted with the practicalities of home-building. The results are used to examine the significance of experiences in childhood and adolescence in influencing adult behaviour for general fields of marketing and social interest.