Evolving software systems requires their preliminary analysis and assessment. In particular, information on the performance and costs of software system components must be gathered for identifying the most appropriate strategy for their evolution. A critical point is finding suitable data gathering means to effectively support the decision makers. This paper presents a strategy composed of a methodological approach and supporting toolkit to help maintainers in the evolution process. The strategy integrates measurement and decision-making tools, and critiquing techniques. It analyzes software systems and identifies a set of alternative evolution approaches by mapping critiques to specific innovation actions. The proposed strategy is validated by case studies conducted with a major software enterprise and Public Administration.