The subject of orthotics is complex but there are some simple principles and examples that should give you an appreciation of their benefit. First of all, orthotics can be scanned or custom molded. The scanned device gives added shock absorption but fails to control excessive motion and breaks down much quicker. They are less expensive but tend to loose their benefit within 2 to 3 months versus custom orthotics that can last up to 2 years. Custom molded orthotics are made specifically for each individual patient's foot. They can be done with plaster molds.