Before you start testing any aftersales tactic, you need to define your objectives and how you will measure them. For instance, do you wish to increase repeat purchases, referrals, reviews, upsells, cross-sells, or customer satisfaction? Depending on your objectives, you will need to select the right metrics and data sources to track your performance and compare different tactics. Some common metrics and data sources for aftersales are customer lifetime value (CLV), customer retention rate (CRR), net promoter score (NPS), customer feedback, and customer behavior. CLV is the total revenue generated by a customer over their relationship with your business. CRR is the percentage of customers who stay with your business over a given period. NPS is the likelihood of a customer to recommend your product or service to others. Customer feedback is the opinions and suggestions of your customers collected through surveys, reviews, testimonials, or social media. Lastly, customer behavior is the actions and interactions of your customers with your product or service such as usage, engagement, purchases, or churn.