Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

^ yes, rental stock, even if unused, based on insurers req's. Would same "rules" not be applied to retailers by their insurers? If not why not?

Any limitation on sale by age would be the responsibility of the manufacturer. Unless the maker tells the shop to return/destroy anything unsold after a specific date, the shop can rely on passing responsibility for age-related failures to the manufacturer.