Wireless sensor networks are an active research area due to their wide range of applications in almost every aspect of life and their associated challenges, including energy conservation, longer life cycle, and better utilization of resources. Their presence in such large quantities also leads to a tremendous amount of sensor data to be stored and processed efficiently. This poses a new challenge as the sensor nodes are often deployed in harsh environments, where cheaper resources are needed to collect and process data. Data reduction is one such technique that helps in reducing the amount of sensor data. In this paper, a review of data reduction techniques has been presented. An analysis of various data reduction techniques proposed over the years, their benefits and challenges, how they help, their pros and cons, and if the employment of data reduction techniques is worthy in such resource-constrained environments has been presented.