If a helmet sits in a box for 10 years, I'd have full confidence its fidelity. A 10-year old helmet, even if never wrecked, has likely been seen its share of bumps and scrapes. My wife, who has ridden with me dozen times or so this year has probably dropped or banged around her helmet about a half-dozen times. I am obsessive with my gear but I know that it sees its share of abuse in luggage, in the back of the vehicle, etc. I'm willing to drop $150 or so every handful of years to protect my head even if I don't need to.