There is always a balance between different types of hearing aids and their advantages and disadvantages that influence choice of device and ultimately user preference. Personal choice also plays a role when deciding on behind the ear or in ear hearing aids. In this review the authors address the fitting approaches and discuss the differences between closed hearing-aid fittings and open hearing-aid fittings. Improved conversation in hearing aid users is achieved by improving audibility, speech recognition and dynamic range. Poor comfort and poor sound quality are noted as the main reasons for not wearing aids. One of the main issues with a closed hearing-aid fitting is the occlusion effect. This occurs when a custom made ear mould prevents the escape of bone conduction sounds out of the canal resulting in the speaker’s own voice becoming too loud or ‘boomy’. The review addresses objective and subjective methods of measuring the occlusive effect and highlights that it is more prominent for those with a mild or normal hearing loss in the lower frequencies. The solution to combatting this effect is to introduce a vent into the mould or an open device fitting to make the device more wearable. Other benefits of the open fitting aids include improved comfort, improved sound localisation and cosmesis. However open fittings also have their limitations. Overall the choice of fitting is governed by the level of hearing loss, but in addition to this the authors advocate consideration of the individual’s situation and needs. More approaches to combining the benefits of both fitting systems is also recommended.