When you have a working product what have you found most helpful to measure? Are there certain metrics that have helped you more during start-up than scale-up and vice versa?
I think one metric which evolves over time is the "success achieved" KPI. It might be different for each stage the product and segment of customer, but keeping an eye on it provides a world of insight that can be translated into product development, marketing copy, sales collateral and, training material.