Some helmets are sold with instructions that give you a replacement guide. If a company recommends replacement of adult helmets every two to three years, you may need to weigh that against use. Another way of figuring when bike helmets need replacement is to calculate the hours you use your bike. Many adult helmets are rated at 500 hours of use. If you consistently ride your bike every day for an hour, you’d need to buy a new helmet in roughly a year and a half.
Bike helmets can degrade over time, especially if they are not stored in a proper manner. When you buy a boxed helmet, keep the box. Use it to store the bike helmet safely, away from light, heat, and the potential for other objects crushing it, when you’ve returned home. With safe storage, you can extend the life of a helmet, because even when one is rated for a certain amount of years or hours, damage can occur if the helmet is improperly stored. Always give helmets a thorough inspection to look for any cracks, breaks in the protective foam material, or other obvious defects before using them.