The housing crisis today is not only quantitative but qualitative. While households have become increasingly diverse and dynamic-single-parent families, blended families, boomerang children, home-workers, non-family cohabitations…-housing production remains standardised and rigid. Housing is treated as a market product focused on numbers: price/m², size, CO₂ emissions, construction speed… forgetting that housing does not host numbers, but people. START-Ivry confronts this silent crisis. The project is grounded in more than a decade of research into contemporary ways of living, distilled into 10 Design Principles for Adaptability and 8 for Quality. These principles translate household diversity into concrete spatial solutions. Located in Ivry, Greater Paris, it comprises 5 buildings and 288 affordable adaptable dwellings. Super-adaptable and divisible dwellings, equipped alcoves, movable kitchens, thoughtful distributions… allow housing to evolve as lives change. Here, housing adapts to people-not the reverse. Adaptability becomes a form of circularity at the scale of the apartment. The most sustainable sqm is the one that does not need to be rebuilt. START-Ivry demonstrates that adaptable housing can operate as social infrastructure rather than merely a market product. Achieved within conventional budgets, regulations and construction systems, it unlocks housing capacity, reduces the need for future construction and ultimately contributes to more resilient cities.