Hardware is the core component guaranteeing stability, sealing and safety, directly affecting service life and performance — not merely a 'switch tool'. 1) Determines smoothness and durability: material and craft of handles, hinges and transmissions affect feel and life; quality imported stainless/high-strength aluminium passes 100,000 cycles, smooth for 15–20 years, while poor hardware rusts/deforms in 3–5 years; transmission precision affects sash fit and thus sealing. 2) Strengthens sealing (water/air tightness): hardware is the key joint of the sealing system; quality tilt-and-turn hardware gives multi-point locking that presses the sash evenly onto the gasket, avoiding uneven force from single points; poor lock-point strength causes loose locking and falling air/water tightness. 3) Guarantees safety: hinge load capacity decides whether the sash sags — quality hinges bear 80–120 kg each for large, heavy-glass windows; some high-end hardware adds anti-pry and child-safety locks, especially for high-rise. 4) Enables special functions: hardware design decides opening modes — tilt-and-turn gives 'casement ventilation' and 'top-hung micro-ventilation'; inward tilt eases glass cleaning and avoids high-rise fall risk; poor hardware cannot support complex openings.