The study of purchasing behavior can only be relevant if we take into account the nature of the relationship and the form of the exchange. Some exchanges are transactional and punctuated in time, while others are more relational and unfold over time. What's more, some exchanges are formally contractualized, while others are not. If companies, out of an obvious concern for customer loyalty, are moving towards relationship-based marketing, they will also need to develop a model for analyzing consumer and buyer behavior that is adapted to the type of relationship involved.