Do I need One Hearing Aid or Two? 

Do I need One hearing aid or Two The brain needs both ears. WHY?
1. The brain needs two ears to hear what direction the sound is coming from and
2. The brain processes competing sounds from both ears for improved clarity and a more balanced sound.
Two ears is like listening to music in with two speakers, sometimes called "stereo" versus listening to music with one speaker sometimes called "mono" Mono is like the sound of one person talking: the sound source is fixed in one place.
Stereo is very different. "Stereo" tricks the brain with two loudspeakers where each one plays slightly different sounds and our ears and brains reassemble the noises into a two-dimensional soundscape. Century Hearing Aids 888-295-2944
https://www.youtube.com/watch?v=sD74sdhN_UI