Dual approaches for real-time systems specification try to integrate in a unique model/language the most interesting features of both operational and denotational approaches. In some cases, the object-oriented paradigm has been used for integrating the above aspects and as a support for covering with a uniform approach the development life-cycle from requirements analysis to application coding, by presenting initially a mainly denotational semantics which changes in operational semantics with the increase of implementation details. For these reasons, traditional development life-cycles are unsuitable, and more specific phases are needed to exploit the potentiality of the approach. In this paper, the authors present the life-cycle defined for a dual approach proposed in the literature—i.e., TOOMS/TROL.