Directional microphones & Rechargeable batteries
Directional microphones pick up sounds waves from a specific direction, while omnidirectional microphones pick up sound waves from all directions. Headphones with directionality [7] contain two or more microphones installed at a specific distance from each other within the hearing aid which amplify sounds entering the microphone from a fixed front-facing direction. Directional microphones can increase your ability to hear when you’re in an environment with mixed sounds.
Rechargeable batteries improves maintenance by removing the need to change the batteries regularly and also reduces cost of buying new batteries. Invest in hearing aids with long lasting batteries and you will be better off for it.