Amazon’s Echo and its competitors were at the top of shopping lists this holiday season. And now, social media is buzzing with videos of mishaps and rants from frustrated parents whose kids are ordering expensive toys by voice demand. But if you get past the giant teddy bears in your living room, Echo and other IoT devices carry an important reminder for marketers: know your customer.

There are many different strategies for measuring the value of your customers both individually and collectively. While collective measurements like Average Revenue Per Customer (ARPC) can offer you a holistic view of your entire customer base, it can often be misleading. ARPC can become significantly skewed by the presence of a few big-spenders.