The thing with long videos is this: if they don't hold the audience's attention, they won't be watched all the way through.
A trick with long videos that aren't interesting all the way through (I see a lot of people do this) is to split the video up (as you said). This makes it where if they are interested enough, they can watch the other part. They most likely will if the parts are released all at once.
But the way I like to do it (that is, if I did it) is to make the video interesting throughout that it holds the audience's attention all the way through so it won't need to be done in parts. Of course, there's no guarantee that the viewers' attention spans will be long enough, or that they have the time to watch a longer film.
I do know that a lot of times I am scared off from watching videos because of the length of the video. I'll typically allot about 5-ish minutes max per video if I'm just surfing youtube (unless it's from one of my favorite creators), but anything longer, I'll procrastinate watching until I have the time.
So, TL;DR, splitting it is a good idea if the video can be logically split up. If it's going to be a 5.5 minute part and a 2.5 minute part, that's not logical even if the storyline allows it to be split there. So the best advice I can give in that case is to just go with one part and make it interesting enough to hold the attention of people.
YouTube • Website"Whatever you do, do all to the glory of God." - 1 Corinthians 10:31b