I can understand why accountants know it's really convenient to have an expiration date on these things to recognize income, but the basic concept of purchasing is exchanging currency for a service/product. Purchasing multiple sessions is purchasing a group of promises of service in lieu of receiving the full service immediately. Having promises of service expire is in the same territory as fraud - denial of a purchased service. I could be crazy, but I don't see why the full bank of promises of service cannot be entered immediately with the understanding that the delivery cost of the services gets applied sporadically in the future. Isn't that the same kind of concept as devaluing purchased equipment over time when accounting for a business' assets?