A: We recommend that helmets be replaced regularly (every 3-5 years from date of purchase or first use), even if there is no visible damage to the helmet. This is because the protective capability of the helmet will diminish over time due to dents, dings, and exposure to pollution, harmful chemicals (such as sunscreen), and long-term exposure to the sun. If there is visual damage, such as cracks, dents, dings, crushed or cracked EPS foam, the helmet should no longer be used and be immediately replaced. Even if there is no visible damage, the material inside the helmet that provides energy dissipation during an impact degrades with time.