As the old saying goes, 2 heads are better than one. We could keep going with 2 hands, 2 legs, 2 eyes, 2 ears are better than 1, etc., etc.
But what are the actual advantages?
The hearing becomes much more natural with sounds coming from all around you.
Being able to identify where the sound is coming from is only possible with two aids. Otherwise how can you tell which direction a bus is coming crossing the street without looking?
It is twice as easy to understand the words when others are speaking.
It enables your to participate in conversations when there is noise around you.
The unaided ear tends to lose its ability to hear and understand over time. Both ears need to be kept active.
Hearing is less tiring. Listening becomes more pleasant.
Wider hearing range
A voice that’s barely heard at 3 metres - with one ear - can be heard up to 12 meters, with two ears.
Listening to loud sounds is more balanced.