Survey timing is important. Typical mistakes are to send too soon or too late. Too soon and the customer has not had a chance to truly evaluate. Your collected responses would not be dependable and would no longer reflect the true pulse of what customers think. Too late and the customer can no longer remember the details. The latter would leave you with vague, irrelevant answers.

Your customer has his mind full of many other products and services and yours is just one in a constellation of juggling priorities. So if you want to make it easy for the customer to respond quickly and accurately, establish the timing logic of sending a survey request. 

Example: A friend had called Vista Print to explain that a print order arrived with image reversed and needed to be fixed. The customer service team of Vista Print addressed the problem by reshipping. Within the hour, a survey request arrived in the email inbox asking to evaluate the level of customer service. That's an example of good timing.