This report describes implementation and exercising of simulation models for a portion of user behavior in the library setting. The emphasis is on user estimations of timing and convenience factors of service and how these are affected by actual service. The report begins with an oversimplified view of the user and becomes progressively more detailed. Comparisons across the several models and alternative suggestions are made. Insofar as the study investigates how features of user behavior might be modelled and what results might be obtained, it can be regarded as a part of a feasibility analysis relating to incorporation of a human component in a library system's simulation. A final matter is a discussion of the relationship of this model to other models in this series of reports. (Author)