Hearing aid dispensers (HADs) are fully certified experts who can test hearing and provide hearing aid after-care services. To employ hearing technology, hearing aid dispensers must be qualified and licensed. Meanwhile, audiologists may be able to test and diagnose a wider spectrum of hearing and balance issues. For medically relevant therapies such as balance issues, noise-induced hearing loss, and earwax impactions, an audiologist may be more effective. Both have the necessary training to install, adjust, maintain, clean, and repair hearing aids.