Incremental Implementation

This is the discipline that prevents you from writing 500 lines across eight files and then spending two hours debugging which change broke everything. It forces you to build in thin vertical slices: implement the smallest complete piece, run the tests, verify it works, commit it, then move to the next slice. The source includes practical slicing strategies (vertical slices for full stack features, contract-first when backend and frontend develop in parallel, risk-first to validate uncertainty early) and hard rules like keeping the build green between increments and using feature flags for incomplete work. The increment checklist is straightforward: one thing per commit, tests pass, build succeeds, functionality verified. Most valuable when you're touching multiple files or feel tempted to write more than 100 lines before testing.