50gb of data is enough for watching Netflix.
However when watching 1 Netflix movie you can easily go through 1 GB of data in just watching that one movie.
So if you have 50gb of data on your internet plan then you can usually watch up to 50 movies on Netflix.
So if you watched one movie per day you could watch around 30 movies in a month and have a little data left over.
Or on some days you may be able to watch 2 movies and then other days watch only 1 movie.
I use around 200 GB of data streaming Netflix movies on my Roku TV although my data is unlimited with Centurylink DSL.
But if you have a data limit then you have to watch your data use and can go through it very quickly.