Beginning with a brief review and classification of model development approaches, we characterize the simulation model life cycle as comprised of seven phases: the conceptual model, the communicative model, the programmed model, the experimental model, model results, use of the model for integrated decision support, and the modification and extension of of the model. This characterization places severe requirements on the task of model management (creation, acceptance, use, revision or extension, and reuse). The Conical methodology has been developed in response to the needs that predominate the model development phases (from conceptual model to model results). Definitions used in the Conical Methodology are explained, and the approach is illustrated with a machine repairman example. An incomplete critigue of the result and the approach concludes the paper.