Why it matters
Good design is invisible until it is missing. Breakpoint shapes how quickly someone understands a page and how confident they feel acting on it, which is the difference between a polished impression and a confusing one. It is where craft and clarity meet.
In practice
In practice we resolve Breakpoint early, in low fidelity, before a single pixel is polished. Decisions live in a shared system so they stay consistent across pages and easy to evolve, and we test them with real people rather than trusting taste alone.