The length of time an orthotic will last depends upon the material it is made from, how often the level of activity engaged in while wearing them. Softer materials wear out every year or 2. It does not necessarily need to be replaced at that point, it may need refurbishing which is less costly. Harder materials such as polypropelene is extremely durable and can last a lifetime if there are no changes to your needs or measurements. Orthotics made of graphite may wear after 2-3 years if used in active sports with high impact or by heavy people.