What effect does mild noise-induced hearing loss have on you?

Not much. Perhaps some slight tinnitus or trouble understanding people in background noise.
Hearing loss. Quiet room, one on one, majority of people with mild noise induced hearing loss will do fine and not notice any difficulty. What you may start to notice is difficulty hearing in crowded situations, on telephones or listening to television or when there is a lot of other background noise. May also start to develop ringing in the ears (tinnitus).