"Many helmet manufacturers have crash helmet replacement policies that offer you a reduction in cost for a new helmet depending on the age of yours at the time of the incident. Refer to the warranty information that accompanies your particular helmet to determine whether a crash replacement policy exists."
This quote was from the manufacturer. I had bought myself a new helmet because mine was 5 years old, but the new one didn't fit me nicely like the old one did. My neighbor loved it so I gave it to him. A month later, he fell off my horse. He didn't want to replace it because it was brand new, but I felt bad because he fell off my horse, so I took advantage of the "replacement policy." I still had all the packing materials and the paperwork because the helmet was brand new.
Big mistake. They only knock off about $5 off the price of a new helmet, and they make you pay the shipping, which was $13. I could have bought a brand new helmet on Amazon for cheaper than the replacement policy. ANNND you must have the original box and the original paperwork (which I did because it was brand new and I hadn't gotten around to throwing it away) to use the policy. Not worth it!!!!!
But, for sure, replace the helmet after ANY fall, and replace after 5 years.