You often don't have to watch a movie to know there's a problem.
You just have to know how to do some online research or have discerning friends.
For example, the movie Unplanned just came out.
The R rating is a no-no automatically for me (they give that rating for a reason), but even if it weren't for that there are other red flags.
I know of some review sites that may not have the greatest of discernment in everything, but a person can look to see if they list bad language in a movie (there are probably 7 or more bad words in Unplanned listed on one of the sites - these sites often can miss something).
You can also check to see whether there is immorality or immodesty in a given movie that they caught (which usually means the immodesty can be really bad when they notice it - since they don't have the same standards I do), etc.
Here are some sites that aren't that spiritually discerning - just a little helpful when looking for the types of things I mentioned:
For the movie Unplanned, it was brought to my attention that Kris Vallotton of Bethel Church, Redding, CA is in it.
That is a HUGE double triple no-no.
Bethel Church is a cult that brings people from all over the world in to be deceived.
The movie is about a Catholic. Roman Catholics also have another gospel, so that's an interesting alliance...and means that there would not be any real Gospel in the movie.
Plus, I saw a couple of other reviews.
I wouldn't have bothered to watch the movie if I were these guys (but I'm not), and I would recommend avoiding that particular movie to everyone else.