When to Rewrite vs Refactor

Research shows that rewrites fail 67 to 79 percent of the time. The median timeline is 16 months with costs between $1.8M and $4.5M. If you're considering a rewrite, you're probably better off refactoring incrementally.

Use the Strangler Extraction pattern. Form a team from existing employees. Define a clean interface. Build the new module as a standalone unit. Route traffic through a proxy. Cut the old code. Each extraction is a finite project with a hard deadline.

The exception: when the current architecture prevents any further development and the cost of incremental extraction exceeds the cost of a rewrite. This is rare. Most teams that think they need a rewrite just need better boundaries.