should be sold today can be sold only today. therefore, to adjust customer demand by setting appropriate price which brings appropriate sales volume is more important. adjustable price is frequently applied to services, for example, higher price for high season and lower price for off season.
the quality of a service is sometimes decided by customers buying it. for example, service level of language school is decided not only by the level of trainers but also by students. if there are some students who are not so motivated in the class of the school, service level would be lower and it affects other students. to avoid it and keep only motivated 