What is the permissible duration, in Sharia, for returning goods to a merchant?

There is no specific duration for returning merchandise due to a defect, unfairness (ghabn), or deception. It is permissible to return it whenever the reason is found, except in the case of tashriya (leaving milk in the udder of an animal to make it appear fuller), for which the duration is three days. As for the option of stipulation (khiyar al-shart), it extends for the agreed-upon period. Rescinding a sale by mutual consent (iqalah) is permissible at any time.