I can personally relate to this, since I wear hearing aids in both ears. Before I had them, my husband would ask if I had heard certain things; I would say I did not, which made him concerned.I would also have to ask students, over and over, what they had said; we have all had the soft talkers, which made it that much harder to hear. Being in traffic, where you need to heard horns blowing or tires screaching to a halt, is also an important situation to have good hearing. Not being able to hear a collegue trying to get my attention, in traffic, was what finally got me to get hearing aids.
In reference to students, they need to hear the instructors; this appies to hearing their fellow students, as well. In reference to home, any student who has children would need to be able to hear the child's cry. Other things include hearing a door knock or door bell, a kitchen timer when cooking or baking, a phone ring and the person on the other end.