It is radically less expensive to keep a customer than it is to find a new customer. In order to keep them we must be certain they approve of the quality and value of our products and services. The only way for us to be certain of this is to ask our customers. Start with these questions.
Most folks have difficulty answering open ended questions.
Our job is to make it easy for them to give us feedback, so we alter the question. Ask for ratings on several categories, especially those mentioned in your mission statement and your strategic objectives. This is when to ask these open ended questions. Keep asking these questions. Keep making the changes they recommend.