For projects where the estimated rewrite duration exceeds three months, we have employed an iterative approach to refactoring for several years. This methodology has yielded pretty good results.

We also utilize a series of Bash scripts designed to monitor the refactoring process. These scripts collect data regarding the utilization of both the old and new "state" within the codebase. The collected data is then dumped in Grafana, providing us with a clear overview of our progress.