Subtitles can make you understand the conversations better and follow along closely. There are some movies that I find it hard to understand their accent and pronunciation, so subtitles make me follow along with moves well.
Depends on the movie. Sometimes I just turn on the subtitles because the area around me is loud, or I'm having a hard time hearing the dialog. Or if I can't understand them. But often I usually only use subtitles if I'm watching a foreign language film or something. I can't stand American voice overs, so any foreign movie I watch, has to be subtitled.
