Yes, customers can generally trade in old mobile phones at Optus Shops. This trade-in program allows individuals to receive credit towards the purchase of a new device or plan. The specific value of the trade-in will depend on various factors, such as the model, condition of the phone, and any applicable promotions at the time of trade-in. It is important to note that devices are usually evaluated on a case-by-case basis, and customers might need to provide certain details about the phone being traded in, including its functionality and any visible damage. For the most accurate and up-to-date information regarding the trade-in process, potential customers may want to visit the current Optus website or the nearest Optus Store to inquire about specific procedures and requirements.