How to Measure ROI of Refactoring

Use the TCC framework. Project your current system's cost trajectory over 12 months. Then project the cost after modularizing one component. The gap between the two curves is the ROI of refactoring.

In a welded system, cost compounds as features accumulate. In a modular system, cost rises linearly. The divergence accelerates over time. Measure the gap at quarter four versus quarter one. If the gap is widening, refactoring ROI only increases with time.

Include the cost of incidents, slower feature delivery, and engineer turnover in your projections. These are real costs that refactoring reduces.