1. A therapy delivery system for an individual comprising: a therapy dosage module comprising a first control algorithm replaceable with a second control algorithm customized to needs of the individual, the first and second control algorithms being defined to determine therapy for the individual; and a simulation module for providing a test environment simulating at least one or more physiological conditions of the individual and enabling testing of the second control algorithm when implemented in the therapy dosage module in the test environment before being used in the therapy delivery system to deliver the therapy determined by the second control algorithm to the individual.