I think it is a very individual thing and left mostly to conscience.
They do have articles in the magazines that will give you the idea that a "true chrisitian" wants to be careful about watching things that would offend Jehovah such as spiritistic or demonic things or extreme violence or pornography.
Still you will have ones that will watch Harry Potter with no issue and others that will be scared of inviting demons into their home if they were to do so.
We recently had a sister tell my son that Dr Strange should not be watched because the bible warns against witches and magic and therefore we do not want to be entertained by such things.
Some will walk out of the cinema if something questionable comes up and others will stay put because they spent the money to go.