I came from a school with a large Hard of Hearing population... I've really come to appreciate captioning on all videos. Mainly I just don't like listening to people say things very much, most videos have super annoying soundtracks and effects or other distortion, and really reading is just as effective.

Have captions on your video for everyone, not just the deaf people in your audience (unless you just really love the sound of your own voice so much that you want to force other people to suffer through it).