A good way to discern if a product or service is a need to have is to see what happens if it breaks or is no longer available. Would customers come kicking and screaming? Or, would the day pass by with little to no utterance? (No, not advocating you deliberately break your product.)
Of course, there’s another effect that can be much harder to realize – how effective was the product or service the first time that additional sales were not necessary. Or, there’s a much longer time between sales that effect can be harder to discern outside of problems.
You can count companies with fantastic quality such as Toyota, a great mattress company, Terminex (or other pest extermination companies), etc. In these cases, referrals and customer satisfaction records may hint at the lasting effects of products and services. Feedback is paramount to the growth of these companies.
Lasting effects is a big deal. They require quality. They require an emotional tie-in to be remembered. They require empathy for the customer to know what is needed. Products, services, and even relationships – personal and professional – require a strict focus on lasting effects.
Consider the lasting effects of the product or service as a measure of success. Consider succession.