Most hearing aids sold within the United States have a 30-day trial period. The person purchasing the hearing aid may elect to return the hearing aid anytime within the 30-day trial for any reason. However, the person that sold the hearing aid may charge a fee for restocking the hearing aid. The terms and the regulations of the trial period and the amount of the restocking fee vary widely and so all aspects of the trial period and potential return options should be discussed and put into writing prior to any hearing aid purchase.
Some hearing aids may have trial periods extending past the standard 30 days, but the extension is at the discretion of the person selling the hearing aids and should also be discussed and put in writing before the hearing aids are purchased.
Most hearing aids also come with a warranty.