incremental-implementation

Break the feature into thin vertical slices where each slice delivers working end-to-end functionality. After each slice, run the test suite and build, then commit before starting the next slice so the codebase never sits in a broken state.

Vertical slicing builds one complete path through the stack per increment, such as database plus API plus UI for a single operation. Each slice leaves the system working and testable, unlike horizontal layers that deliver nothing usable until the end.

Use feature flags whenever a feature is not ready for users but you need to merge increments to the main branch. Gate the new code behind an environment variable or config flag that defaults to off, keeping incomplete work invisible.

Skip it for single-file, single-function changes where the scope is already minimal. The overhead of slicing, per-increment verification, and separate commits adds no value when the entire change is small and self-contained.

Mixing refactors with feature changes makes both harder to review and debug, since a regression cannot be attributed to either change cleanly. Separate commits keep each change atomic, revertable, and easy to bisect.