No matter what I'm playing, one of the first things I do when adjusting the settings on a new game is turn on any and all options for subtitles. Cutscenes, dialog, ambiant NPC chatter, whatever. I find myself doing it with movies, too.
I'm not hearing impaired in any way. I just always feel like I'm going to miss something if I'm not able to read along with the dialog. I'm also terrible when it comes to remembering names (real and fictional), so subs help me keep track of who's who.