Customer retention is a measure of how many customers are returning to purchase from a business over time, whereas revenue retention is an indication of how much money those customers are spending with the company. Revenue retention helps businesses understand the overall lifetime value of their customers and identify areas where they can increase customer spend. Both metrics are important for understanding customer behavior and fostering long-term success. However, it's essential to track both metrics in order to gain a full perspective on your customer base and make informed decisions about your business strategy.