Almost all movies made after the 1970s I must have subtitles to know what is being said by the actors. On the other hand, there are very few old movies I need subtitles for...I think in those days talking was more important than background and music soundtracks. Also I know a lot of silent film stars did not do well after sound was added because of accents, etc.

I have subtitles on most all the time. Bad ears and too much background music while the actors are all but whispering to each other.

I have used subtitles since they were available on DVD and especially love the SDH. You catch many subtle noises you might otherwise miss. I love foreign films and opera so got used to being able to read the script and watch the action.