There’s something kind of fascinating about when a franchise makes it to movie number four. Think about all the round trilogies that exist – Back to the Future, The Dark Knight, The Lord of the Rings, the Dollars movies, the Godfather films. So when three movies feel just right, why do franchises bother to go for a fourth?

We could be totally cynical here and say ‘well, if people will pay to see another one, why not make a fourth movie?’ and sure, this is true, for the most part. However, there are examples of fourth instalment movies that genuinely work. Mind you, there are also many that are pure s***e.

First, let’s consider some of the fourth franchise instalments that haven’t worked. We’ll start with these because 1. There are many and 2. We might as well get the cynical/pessimistic POV over and done with.

The action genre in particular seems to be a devil for this trend, examples including the Rambo and Terminator movies. While each had two strong movies to kick off their respective franchises, by movie number 3, the quality of both franchises depleted significantly. Going for a fourth instalment was unnecessary and greedy with both 2008’s Rambo and 2009’s Terminator Salvation getting deserved negative reviews (and underperforming at the box office, though by no means failing).

Rambo felt like a particularly desperate attempt at rejuvenating a franchise that no longer felt in touch with modern audiences. It’s worth noting here that the original Rambo films functioned as a veiled criticism of the Vietnam War. 2008 Rambo practically glorified war and violence.

Other examples of fourth instalments that didn’t work include Live Free or Die Hard, which manages to be less fun or coherent than any of its predecessors (and yet they made another one after that…) and last year’s Jason Bourne. Putting aside spin-off The Bourne Legacy and considering just the Matt Damon movies, Bourne, as it was known in some territories, was a completely unnecessary addition to the already near-perfect Bourne trilogy. Most viewers just pretend it just never happened.

There’s also Fast & Furious 4, aka Fast & Furious (because they had to save variations of the phrase for subsequent movies), which is the worst instalment of that franchise. Don’t fight me on this. It is complete and utter muck.

On the other hand, there are fourth instalment films that have had more effort and thought invested in them. Those that don’t betray their predecessors, or attempt to bring a character to a new generation but feel calculated and cold in the process, or function as a mere tack on for the sake of box office gold. Examples I’d like to draw on here include Lethal Weapon 4 and Shrek Forever After.

While I grant you that these films are by no means the best chapters in their respective franchises – Lethal Weapon 4 was just ok while Shrek Forever After was an improvement on Shrek 3 but still not up to the standard of the others – they were loyal to the characters and themes of their preceding films. Moreover, both effectively used the family unit to give fans that feel-good factor. It’s also worth noting that the time period made between each of these franchise’s instalments was not too big (unlike the twenty year gap between Rambo III and Rambo 4), thus the momentum and audience investment in these movies and their characters hadn’t deteriorated.

Then there are the number 4 movies which, if not considered the best instalments in their franchises, have certainly earned a cult classic status. Movies that came in the middle of long-running franchises like Rocky IV and Harry Potter and the Goblet of Fire are beloved by their fans because they’re well-made, entertaining movies.

Let’s not forget either that there have been those movies which have successfully returned to and rebooted their franchise such as Mad Max: Fury Road, which is pure, adrenaline-pumping, crazy, brilliant action. Mission Impossible: Ghost Protocol, meanwhile, would be an example of a fourth movie that was able to reinstate a sense of coolness into a franchise that was starting to get just a bit too silly.

And, lest we forget, there’s Star Wars IV: A New Hope, which, I’m aware, wasn’t the fourth movie made, but it was the fourth movie. And that’s one of the best movies of all time. So there.