consumer behaviour means study of how consumer as an individual or in group behaves in the marketplace to select,buy,use various goods and services to satify their needs or wants . thus it important to study consumer behaviour as understanding it is essential to the marketers and make decisions accordingly. with this the following are the importance to study consumer 

1. marketing decisions - marketing strategies and programme are important for the marketers to make decisions regarding promotion ,price etc. so it is critical to study consumer behaviour for marketers so that they can prepare and make better marketing programmes as keeping in mind consumer behaviour helps them to achieve marketing goals .
2. market trend - studying  consumer behaviour helps marketers to forcast future trends in the market as it helps to identify upcoming needs and wants of consumer and grab the opportunity and take first mover advantage. 
3. retaining and creating new consumers -  continously studying and monitoring consumers behaviour helps marketers to know the changing tastes and preferences of consumer and offer products accordingly.thus marketers can create and retain its consumer easily .
4. competition - competitionin the market is growing day by day so analysing consumers trends in taste and preferences is useful for the marketer to survive in the intense competition and serve its consumer better than its competitors.