The brain analyses sound by comparing signals from both ears. So when one ear hears less well, working out where a sound comes from becomes harder.
Benefits of two-sided hearing
With both ears working it is easier to locate sound, speech in noise is clearer, and listening takes less effort — you feel less tired by the end of the day.
Are two devices always needed?
No. If the loss is in one ear only, or the second ear would not benefit from a device, one may be enough. The decision is based on the audiogram and your lifestyle.
Next step
A specialist will tell you which option suits you after a hearing check.