Are movie sequels necessary and enjoyable?

As part of the audience, I love sequels so there is absolutely no reason why directors should not make them. But there are certain things that define whether making a sequel of a certain movie is a good idea or not. The most basic requirement for a sequel is that the 
audience needs to love the first instalment and its characters - then the need to know more is natural. A sequel is only as good as the film it's based on, so if the first instalment was a dud, then there is no reason to make a sequel even if the script satisfies the sequel conditions. 
Secondly, an important element is the storyline. There are certain stories that cannot be told effectively in one episode or instalment and that's when one should start thinking of a sequel. For example, my favourite sequels come from the Marvel Cinematic Universe, which basically thrives on longer installations, but when it comes to movies like Titanic, making a sequel would be foolish. 
For a good sequel, the storyline should be able to continue from the first instalment in a significant manner and offer something new within the same setting. The main characters' progression within the story is also to be considered; if Jack has died at the end of Titanic, then it doesn't mean you introduce his brother and make Titanic 2. A good sequel needs the original principal characters with their growth from the previous film intact within the storyline. 
These days, especially in Bollywood, sequels are just using the name and the principal cast members from the first instalment with a total different storyline and characters (you can see this in movies like Golmaal Returns, Singham etc). Most of the time, there is no connect to the previous films and such movies should not be considered sequels. These are just franchises with the aim to cash in on previous successes and are never a good idea.
- Hamza Shafique 
Is the movie blogger behind  www.dubaidesireviews.blogspot.com. You can keep up with him on Instagram @dubaidesireviews
Sequels are something that have plagued the cinemas since the time cameras started rolling. Most of the time, we find that independent, self-contained stories are the ones which work best. Then, once the film gains enough popularity, the producers try to milk a franchise out of it by making sequels. The worst part about these movies? They are just inessential.
Every time a sequel is released, it happens to be underwhelming and uninteresting. Time and again, we see that all these sequels try so hard to be like the first movie, or the previous iterations, and end up being completely chaotic. Majority of sequels these days face a tonal shift; the first movie is about a concrete plot while the second movie focuses much more on comedy or action than the script, and that turns it into just another passable movie.
Data analysis from a review aggregator website shows that there were over 550 sequels between 1996 and 2017, and less than 35 of these films were better than the originals.  So, what about the other 515 movies? All they did was make money for the producers. Just look at movies like Smurfs 2 and Grown Ups. The first movies were just about bearable; the sequels were riddled with too many awkward situations and forced humour.
That being said, sequels aren't necessarily bad all the time. The Marvel Cinematic Universe is one huge movie making machine which has been pumping out sequels since 2008 and most of them have been amazing, with excellent storytelling and visual effects. That's proves that there is a right way of making sequels - planning them out well and executing them properly. But the issue is that most major film series are just intent on making a passable movie for the mainstream audience to rake in a little more money.
In the end, sequels seem to lack creativity, destroy originality and kill whatever goodwill the original movie had gotten. So, I would say that it's better for a filmmaker to stick to individual movies. 
- Pradheepan Raghavan 
Is a vlogger who reviews movies at www.youtube.com/MegaPradz. You can keep up with him on Facebook, Twitter & Instagram @Pradz101.