Understanding the customer lifecycle is fundamental both in product design and customer management (CRM) in order to optimize engagement and, consequently, increase revenue and product sustainability. There is plenty of information on the web about what lifecycle is and its importance in business , marketing and strategy optimization. However, there is almost no information or references about how to measure the customer lifecycle. The little information out there is scarce, theoretical and subjective. Measuring the customer lifecycle allows us to understand which is the best time to send a promotion or to know how much time is needed for a customer to understand your product. The purpose of this article is to provide an objective and practical way to model and calculate the customer lifecycle in order to be able to define and set up marketing and product strategies with a better criteria.