Customer retention refers to a company's ability to keep existing customers over time, serving as a critical metric for assessing business success through ongoing value delivery and relationship building. High retention rates are linked to increased customer lifetime value, reduced acquisition costs, and sustainable growth, contrasting the ineffectiveness of focusing solely on customer acquisition, akin to filling a leaky bucket. Retention is often measured differently across industries, such as e-commerce focusing on repeat purchases and SaaS on subscription renewals, but the goal remains to maintain customer relationships for as long as possible. Retention is crucial for company growth, providing a higher return on investment compared to customer acquisition, with studies indicating that a minor increase in retention can significantly boost revenue. Despite its importance, many businesses prioritize new customer acquisition over retention, often overestimating their customer service quality, which can lead to poor experiences and low retention rates. To accurately track and improve retention, companies can use digital analytics platforms that offer insights into user behavior and help identify at-risk customers, optimize user experiences, and adjust marketing strategies effectively, as demonstrated in case studies like those of Kast and Scrambly.