AI Milestone Experiment Results: 68% of Developers Say Development Without AI Is Difficult… Design Phase Utilization Surges

The AI Milestone program planned by Tech Strategy was an experiment in which approximately 100 developers participated for about three months, receiving credits for commercial AI tools and validating their applicability in work. Participants used an average of 3–4 AI tools concurrently per person; initially, combinations of Cursor and Copilot were common, but the usage rate of Claude Code gradually increased by approximately two times, emerging as a major tool. Analysis by work stage showed high perceived time savings in code writing and debugging/testing. Notably, the positive response rate in the design phase surged by 21.2%p, from 63% in the first month to 84.2% in the third month, indicating that AI is increasingly utilized as a design partner. In the third-month survey, 68.4% of developers responded that 'it is difficult to develop without AI tools,' and 65.3% recognized AI at a level of 'junior developer' or higher. However, trials and errors were also reported, such as lack of context and increased verification costs. Meanwhile, some senior developers are evolving collaboration methods by establishing multi-agent workflows that operate multiple AI sessions simultaneously.