Today I had the chance to meet with a long-time client and friend who, along with her daughter, is considering an ecommerce startup venture. It was so exciting to hear the fun plans of ramping up a new business idea.

Before you invest significant time or money into an ecommerce idea, run the numbers. What does your unit economics look like? What are the platform fees for your target marketplace? What’s the realistic ad spend to acquire a customer? What does inventory cost and how long does it sit? These questions don’t kill great ideas — they make them better. Knowing your numbers before you launch is the difference between a hobby and a business.