As machine learning (ML) systems become central to critical decision-making, concerns over fairness and potential biases have increased. To address this, the software engineering (SE) field has introduced bias mitigation techniques aimed at enhancing fairness in ML models at various stages. Additionally, recent research suggests that standard ML engineering practices can also improve fairness; these practices, known as fairness-aware practices, have been cataloged across each stage of the ML development life cycle. However, fairness remains context-dependent, with different domains requiring customized solutions. Furthermore, existing specific bias mitigation methods may sometimes degrade model performance, raising ongoing discussions about the trade-offs involved. In this paper, we empirically investigate fairness-aware practices from two perspectives: contextual and cost-effectiveness. The contextual evaluation explores how these practices perform in various application domains, identifying areas where specific fairness adjustments are particularly effective. The cost-effectiveness evaluation considers the trade-off between fairness improvements and potential performance costs. Our findings provide insights into how context influences the effectiveness of fairness-aware practices. This research aims to guide SE practitioners in selecting practices that achieve fairness with minimal performance costs, supporting the development of ethical ML systems.