It would depend on your capacity to watch movies. A lot of movies are roughly 2 hours each. People can probably watch about up to 8 movies a day if they would like to. For people who would like to watch shorter movies, they can probably increase the number to 9 or 10 movies. People should not watch a lot of movies in a day though.
Too many movies can make people’s comprehension duller than usual. Watching about 2 movies can be great but aside from that, you should refrain from watching too many movies in a day. Take note that some people watch movies and watch the television after. This can be bad for the eyes too as they are not given a chance to rest.